Efficiency
by NotWeird
Summary: Nanako is a low-maintenance girl who lives by the rule of maximum output for minimum input. Unfortunately for her, she lives next to (and regularly babysits) a high-energy All-Might fanboy. It's not so bad, except for the fact that he grows up to be a main character- which she definitely didn't sign up for when Inko-bachan asked her for a "small favor."
1. Chapter 1

**A/N:** My first BNHA/MHA fanfic- hope you all enjoy :)

* * *

Nanako yawned tiredly as she rolled out of bed and trudged to the bathroom. Precisely seven minutes later, she walked out with clean teeth and a fresh face. It took her twelve minutes to get dressed and fix her hair, after which she'd have a quick bowl of cereal or maybe a granola bar and some fruit for breakfast. It was cold out, so she'd have to fill her pre-prepared thermos and grab her jacket but that time was already accounted for. A glance through her bag to make sure she didn't forget anything, then out the door she'd go, ready to take on the day.

Well, that's how her morning _usually_ went. Partway through taming her thick hair, there was a sudden knocking at the door and a muffled voice asking if anyone was home. She ignored it at first, but when Kenta didn't get up to answer it she knew he'd stayed up too late studying and that meant it fell to her to deal with.

She bit back a scowl and left her hair loose as she padded across the messy living room. There was a second set of knocks, which she would have been more upset with if the person on the other side hadn't been Inko Midoriya, her kind (if overly emotional) neighbor. True to what little she knew of the older woman, Inko was mildly flustered and busy fidgeting with her skirt and briefcase when Nanako opened the door with a curious tilt of her head.

"Ah, good morning Nanako-chan," she greeted with a distracted smile. "Is your cousin awake?"

"Good morning Midoriya-san," she replied politely. "And, no, Kenta-nii's still sleeping. Did you want me to get him?" He was going to be grouchy but he did have class soon so it wasn't like he could get too mad at her if she tried to get him up now.

She muttered under her breath then lit up when her eyes landed Nanako's school uniform. "Oh, you're in middle school!" she exclaimed on the verge of happy-crying. "That's wonderful-" Nanako was suddenly concerned- "I was wondering if you could do me a favor and walk Izuku to school? I wouldn't want to bother you normally, but he's been having some trouble with his classmates lately and I don't want him going alone. I get so worried about him, you see…" she place a slender hand to her soft cheek and a few tears slipped out.

No, no no, _no_ no no, **no**. Her mornings were carefully structured and timed so she could maximize her sleep and minimize the possibility of running late- she couldn't just add a whole other person into her routine at the drop of a hat! Especially not a little kid like Izuku who probably thought she had cooties or something.

Despite her screeching internal monologue, she was weak to the woman's tears and found herself nodding along to the request with a dutiful "I can do that, Midoriya-san" spilling from her lips. Wanting nothing more than to slam the door in her neighbor's face, she let the rambling tone wash over and tried to find her inner peace while also recalculating how much time she had to get ready. Cereal was out the picture unless she wanted to eat while she walked, and her hair still needed to be tamed from the frizzy, half-knotted mess it currently was… She vaguely heard the words "just for this week" and felt her soul detach from her body.

Finally, Inko finished and scrambled out the door with a nervous cry of "I'm late!" Nanako didn't bother to watch her leave. Instead, she quietly closed the door and piloted her soulless body back to her room to finish getting ready.

 **-[-]-**

Izuku wasn't a terrible person to walk to school with. She followed his lead on the way there, carefully noting on her phone what streets they needed to take in place of looking it up with GPS so it'd stick more in her mind. It was cold enough to see their breath fog in front of them and a smattering of freckles peeked out over the edge of an All Might scarf when she offered to share her thermos of hot cocoa. He refused with a quiet murmur and though his jacket was plain, he also had a pair of All Might shoes and she was pretty sure his lunch box was themed after the #1 hero. Thankfully, he didn't talk her ear off about how great All Might was; she got enough of that at school from Raito, the overly loud fanatic in her homeroom, thank you very much.

It was then that she decided she wouldn't _hate_ having to walk him to class for the week (though all bets were off if she got stuck with babysitting duty for longer than that). She left him at the school gates with a perfunctory "have a good day" and scurried past the slow crowd of elementary students to her own school, making it with a few minutes to spare. With a click of her tongue she took her seat and drafted a new morning schedule to accommodate her neighbor- she didn't like being rushed or having her designated pre-homeroom relaxation time cut short.

She picked him up afterschool and his Inko-genes were suddenly out in full force because there was barely a quiet moment between them until they got home to their respective apartments. He wasn't loud, per se, but he was definitely chatty enough for the both of them. The chattiness continued the next morning when he asked her what who her favorite hero was, and she (guiltily) used her quirk to mellow him so he wasn't talking as fast as a hummingbird when he started rambling. (Being her own island of calm was handy sometimes.)

 **-[-]-**

After the _resounding_ success of their week-long test run (Izuku didn't get bullied less by any appreciable amount, but he also didn't get bullied _more_ ) it was decided that the two of them should walk to school together every day. Kenta-nii, the traitor, didn't disagree and went as far as to point out that it would be safer/more logical for them to do so; the buddy system and all that. In return for that bit of treachery, Nanako ate the last of the lemon pepper chicken wings that he'd been eyeing.

In contrast to Nanako's irritation, Izuku was excited because it meant he was no longer lonely in the mornings or afternoons, which helped to subtly change his classmates opinions about him from "completely friendless loser with no quirk" to "quirkless nobody." No one ever came up to him to ask who the older girl who walked with him to/from school was or anything, and it still hurt a little [a lot] to have his lack of a quirk pointed out all the time, but the class atmosphere felt a smidgeon less hostile and that helped.

After an initial wave of irritation, Nanako shrugged and resigned herself to it. She didn't hate her neighbor (in fact, she kind of admired how energetic he was since her default expression was "somewhat bored but not zoned out") but having her schedule messed with without anybody asking how _she_ felt about it was incredibly annoying. More annoying was the uppity brat who pointed in her face and tried to insult her by calling her "Quirkless Deku's Quirkless big sister" one random day in January.

She couldn't keep the disgusted look off her face and her response of "do I know you?" was apparently worthy enough of a round of "oooh!"s from the small crowd. Not to be beaten, the kid proudly rattled off their name as though it was supposed to mean something and "taunted" her by insisting that she was "a quirkless loser just like [her] brother" once again.

"No really brat, who _are_ you?" she shifted her weight to one hip with the same look still on her face. "Whatever, it doesn't matter because you're _annoying_." She turned her back on the fuming second grader. "Izuku-kun, let's go."

There was a round of laughter and slightly mean comments behind them about the nine year old currently stomping their foot as the pair walked off, but she didn't care enough to look. There had been a handful of classmates she really didn't like in elementary school, but she couldn't recall ever trying to outright bully them. It was such a waste of time, and as it stood she was already pretty low-energy so mustering up the willpower to actively pick on someone was outside of the realm of her imagining.

Preoccupied with her internal monologue, Nanako didn't notice the sudden stars in Izuku's eyes when he looked at her. He hurried to follow after her with a smile on his face and a skip in his step. No one had ever stood up for him like that before, especially not someone as cool as his older next door neighbor. She didn't deny the accusation that they were brother and sister (wasn't ashamed that anyone would think she was related to a quirkless nobody like him) and even called him by his _first name_ in front of everybody!

That was huge! He could barely believe his luck! He floated on a cloud all the way home, and just when he thought his day couldn't get any better, Nanako turned to him and said "if that punk tries to start anything, let me know and I'll knock them out for you, okay?"

"Yeah yeah yeah, okay!" He nodded enthusiastically then felt a wave of calm come over him, slightly dampening his joy but not taking it away completely. "Thanks, nee-chan!"

"Ah," she blinked owlishly then quickly turned and let herself into her apartment. "Don't mention it."

 **-[-]-**

Nanako glanced at the clock for the fifth time in as many minutes and resisted the urge to scream. Math usually flew by, but that day the second hand ticked torturously slow, mocking her impatience. Her sudden personality switch wasn't without reason: Izuku had carried his homework folder that morning, rambling about the upcoming field trip to a local zoo, and when he'd almost dropped it into a sewer grate after tossing it up in the air in his excitement two minutes prior, she'd taken up the responsibility of carrying it.

The problem was that she'd kept it too, and hadn't realized until she was pulling out her own homework and revealed an All-Might themed folder (to the delight of Raito, the fanboy). After a quick bout of panic, she rationalized to herself that she could just bring it to his teachers after school when she went to pick him up- teachers had to stay behind for at least thirty minutes anyways. If she hurried, she could make it with time to spare.

Her panic rapidly returned when the class reps read of the list of who had cleaning duty that week, because there was no way she could convince anyone to let her skip out so she could "return homework." Nawaguchi had gotten enough jeering from their class when he got excused on account of his mother being sick- and that was a legitimate excuse.

The plan had formed quickly in her mind then, pushing out the panic. Her habit of always wearing earphones meant people liked to talk around her, but most times there was nothing playing, so she knew for a fact that there was a loose section at the bottom of the gate at the eastern edge of the school where the gardening club met and a tree that went over the gate to the north as long as she wasn't afraid of a ten foot drop. The tree she discarded immediately- it'd be good for getting out but not for getting back in.

If she was quick and traffic was good, she could make it in about ten minutes. If not, maybe fifteen- either way, delivering the folder to the front office wouldn't take her long so she didn't need to fret about timing that part of her plan. She could eat on the way too; that'd save her some time and stress.

And yet _still_ the clock ticked too slowly. Her heart thudded in her chest and over the impatient _lub-lub_ she could faintly hear her sensei drone on about variables and systems and graphs. Just when she was about to make a break for the door, dismissal be damned, the bell rang and a shot of relief ran though her. Without much mind for her classmates, she scrambled to her feet and bolted out the classroom, folder in hand.

She made it to the shoddy fence in record time and carefully crawled under. No random teacher or police officer called her out for ditching school, and though her shins twinged with the force of her steps, eleven minutes later she stood politely at the edge of the school secretary's desk only panting a little.

The secretary was a middle aged man with a comb over and a cologne she recognized as being the one Kenta called "try hard: old man edition." It didn't smell _bad_ , but she was on a bit of a schedule and he was drawling lazily into the phone so it became the world's most _annoying_ scent.

She faked a cough, twice, and he finally turned his attention to her.

"Yes?"

"My brother left his homework in my bag," she rattled off the pre-prepared lie and held out the folder; Izuku's full name and class were clearly written at the top.

He frowned, muttered something into the phone, then looked back at her. "Is there something you want me to do about it?"

"Can you call him to pick it up?" she carefully refrained from kicking his desk.

"It's lunchtime," he pointed at the clock over her right shoulder. "Just go to his class."

"Alright," she turned on her heel without thanking him for his help and made a bee-line for the bathroom just outside the ugly faux-wooden doors. _What a useless man_ , she thought, and wet a handful of paper towels to clean the dirt off her shoes.

After wandering for a bit, she caught on to the school's floor plan and hurried around the corner to class 3-A. Conversation quieted a smidgeon as she opened the door, but upon seeing that she wasn't a teacher, it picked back up.

Izuku leapt from his seat and picked past his noisy classmates with the sort of uncanny balance she'd only ever seen in cats. "Nee-chan!"

Nanako grinned at him. "Hey, Izu-kun. I-"

"My folder!" he exclaimed and his already cheery face brightened even more. "I forgot this morning and sensei made me stand up and tell everyone why I didn't-"

Quirk active, she brushed a hand through his hair and he immediately calmed. It'd been an ordeal and a half to get this far, and while she was happy to let him ramble most other times, now was not one of them.

"Well here it is," she glanced up when she heard someone say "I thought he was an only child?"

"Thanks," he took it and looked over his shoulder at his curious classmates' faces. "Uhm… did you want to stay for lunch? Mom packed me some cookies." He turned wide, hopeful eyes her way as the kids behind them gossiped a little louder.

"I still have class so I really need to get going," she reminded him then wanted to kick herself when his shoulders dropped. "But we can stop and get something afterschool if you want."

"Okay," he perked back up, resilient as ever. "Have a good rest of your day Nana-nee!"

"You too, Izuku." she ruffled his hair and left. The walk back was less stressful, and she managed to just finish her lunch before sneaking back into class and getting surrounded by her eager, curious classmates.

"Where'd you go?"

"Do you have a boyfriend?"

"Oh, does he go to a different school?"

"Did you go to meet him!?"

"When did you start dating?"

It was a long rest of the day.


	2. Chapter 2

Kenta-nii was a college student, so it wasn't unusual for him to disappear for a night and crawl back home the next morning. He usually made an effort not to leave her alone for an entire day _and_ night because she was only thirteen, even if circumstances had made her a _responsible_ thirteen year old. Still, he was nineteen and she wasn't his daughter so one Friday morning he took off for a weekend trip with his friends and she didn't find out until afterschool when she read the short letter he left to explain things for her.

He had finals coming up in two weeks and had been really stressed lately so his friend (who had an uncle who owned an inn on a mountain) suggested that they all get together and study. (Left unsaid was the fact that they would do far more than studying since Kenta had taken a few of his favorite video games along.) He left money for food and advised her to ask Midoriya-san if she had any problems; he'd be back Sunday evening at the latest. Scribbled at the bottom was a note for her not to delete his save files off the console.

Nanako pinned the note to the fridge then grabbed a bowl of ice cream and plopped herself on the couch while the TV flickered to life. Anime she'd fallen behind in watching flashed across the screen as episode after episode played. While she switched from one series to the next, she wondered what it was about her that made adults abandon her so easily. Realizing how sad her thoughts sounded (what was some, some crybaby five year old?), she shook her head to clear it and shoveled another spoonful of rainbow sherbet into her mouth. Being on her own wasn't new, and knowing that Kenta would definitely be back before school started helped her feel better.

When she rolled out of bed the next morning with the scent of coffee thick in the air, it was almost like he hadn't left. Reality came crashing back down on her as she walked to the kitchen and didn't see her cousin in the middle of cursing into a gaming headset and knocking back his third cup of milk coffee. She sighed and flicked the off switch on the machine.

What was she going to do for the day? When she lived with her mom during elementary school she used to go out with her friends or go to one of her extra classes, but lately her options had been reduced to hanging out in the living room with Kenta or hanging out in her room alone. It'd been difficult to pick up and move mid-schoolyear, especially in the middle of sixth grade. While at first she'd felt completely abandoned and distraught, she had eventually decided to stop moping around and start talking to others more.

However, by then it was time to graduate and too late to make friends. She then vowed to try harder for her first year of middle school, but found that friend groups from elementary school carried over and it was difficult to gather the courage to insert herself into anyone's conversation. Thus her habit of wearing earphones to make herself seem busy had started, and apparently that given her an intimidating reputation of a calm and cool girl who didn't talk much.

That image was partially shattered when the Lunch Fiasco (as she called it in her mind) occurred, but still her friendships were new things and it would be troublesome to ask anyone to hangout on such short notice. Even if she could scrape enough nerve together to at least ask if anyone was free, in her gut she knew she'd only be setting herself up for rejection.

With a groan, Nanako slumped across the kitchen table and listlessly shoveled cereal into her mouth. She needed a better hobbies than collecting key chains and tending her little trio of house plants- maybe she should join a club? She'd resisted so far because she was kind of lazy (which was also partly why she was bad at making friends) but club day for the spring term was next week…

A knock at the door broke her from her thoughts and she frowned. A quick glance at the clock showed that it was nearly ten; too early for the mail, and her cousin tended to go out rather than invite his friends in. (Not to mention the fact that any friends of his must have known he was out of the city- no one ever showed up without texting first.) She checked the peephole and got a fisheye's view of her neighbor, Midoriya Inko.

Weird. Did Kenta forget to pay the rent before he left or something? Though Midoriya-san wasn't their landlady… She undid the locks and opened the door without delay.

"Good morning, Nanako-chan," Inko tucked a stray lock of hair behind her ear. "Do you know if Kenta-kun is busy today?"

"Good morning Midoriya-san," she greeted politely. "Uhm, my cousin is on a weekend trip- he won't be back 'til late on Sunday so... uh, did you need something?" Despite walking with Izuku to and from school every day, she didn't exactly interact much with his mom (and it showed).

"Yes, I had a little favor to ask," she said with a soft smile. "I need to run some errands and I was wondering if you could sit with Izuku for a little while? He usually goes with me, but he hurt himself during PE and the doctor said he shouldn't be up and about for a few days. He's a good boy so he shouldn't give you too much trouble, especially since he's been playing video games since he woke up this morning."

"Yeah- uh, yes, I can do that," she corrected herself and bit her tongue in reflex; her mother always stressed that it was important to use polite speech with her elders. More than that, she was pretty fond of Izuku so watching him was definitely better than anything else she had planned (which was a whole lot of nothing).

The older woman was pleased and excused herself to let her son know. In short order, Nanako dressed, shuffled over to next door, and received a quick tour before seating herself on the couch next to Izuku. Ever the worrier, Inko made sure to give Nanako her number and stick a list of emergency numbers to fridge before she left, reiterating a few times that her phone's ringer was on and they should definitely call her if anything happened.

Nanako wasn't sure what catastrophe could happen while the other woman was out grocery shopping, but nodded along and tried to reassure her to the best of her abilities. Finally, Inko left and the green-eyed girl sighed in relief. She wasn't used to the attention and it made her chest twinge but it wasn't _completely_ horrible- she could get used to it the same way she got used to Izuku's chattiness.

Speaking (thinking?) of him, he was busy button mashing in a surprisingly methodical manner and glanced away from the fighting game on-screen for the quickest moment to flash her a wide smile.

"Morning," she murmured in reply and pulled out her phone. As she scrolled through Viewtube to find something to keep her entertained, his character (which was All Might in his debut costume) leapt up in the air, spun like a drill, and demolished the computer's character in three short seconds. There was a cut scene of All Might posing and throwing out a quippy one-liner, but by then she'd already clicked on a video and plugged in her ear phones. Between him and Raito, she had more than enough of Japan's number one hero.

The rest of the day passed like so, with a break so they could swap out the melted ice pack for a fresh one and another for lunch. Inko came back around three with arms full of groceries and Nanako hurried to help her the rest. When everything was moved in, she tried to excuse herself but the older woman convinced her to stay for dinner.

Overall, it was a nice (?) experience. Inko chattered happily about her day while she supervised Nanako and Izuku as they peeled and chopped vegetables at the table. When Izuku relayed what they'd done while she was out, she listened and threw a few questions their way- simple things, but it got Nanako talking too and by the time she went home she had unwound enough to consider not turning down the older Midoriya if she needed a favor in the future.

 **-[-]-**

The next request for a favor came soon after: Inko needed to work late and didn't want her son to be alone for so long. Kenta, of course, was busy studying for finals and having small mental breakdowns so it fell to Nanako to do the actual watching even though her older cousin was the one who had agreed. She wasn't really complaining though, because there wasn't much to "watch" about Izuku. He didn't try and run around the house or use the stove without permission, he wasn't loud or rough, and when Kenta told him not to play with the special edition figurines on the shelf, he didn't. If anything, it was more like she was supervising him while he did homework and making sure that he got a snack when he was hungry.

In return for her "hard" work, Nanako was invited to dinner a few days later (Kenta was out drinking to celebrate finals being over, though he was invited too). It was delicious, and she went home with a small container of leftovers.

Then, two weeks later was the end of the fiscal quarter and while neither Izuku nor Nanako had any idea what that really meant, it basically boiled down to his mom working a _lot_ of overtime. Rather than hang around Nanako's (where there was exactly zero All Might merch), they migrated to Izuku's place. He was much happier surrounded by his toys and fanboy paraphernalia, she got to play on her laptop, and Inko paid her in cooking lessons so it was an all-around win.

It got to the point that the following Monday Nanako just instinctively followed Izuku in and when Inko arrived home before the sun went down they both jumped in surprise. The older woman started laughing and Nanako felt a mild flush heat her cheeks.

"It's not that funny oba-san," she grumbled then jumped _yet again_ as Inko burst into tears with a wide smile on her face. "W-wait, what's wrong?!"

She didn't answer except to shake her head and draw the younger girl into a hug. "Oh, you're so cute Nana-chan!"

Wide, confused green eyes swung over to Izuku, but he smiling just as widely and explained nothing. She resigned herself to having the stuffing hugged out of her body, then happily took up Inko's offer of another cooking lesson.

 **-[-]-**

"Hey kid, not to be rude, but why are you always home?" Kenta leaned over her shoulder and swiped at her pencil as she did homework.

Nanako elbowed him. "I live here."

"Well duh," he rolled his eyes. "But don't you have like friends or something? Someone you can hang out with?"

"I have friends," she bit and erased the jagged line he'd made. "But they're… busy with clubs and stuff. We hang out- sometimes." It sounded like a half-assed excuse even to herself.

He hummed sagely. "You should find out what clubs they're in and go hang out with them then."

"Why do you care all of a sudden, Kenta-nii?" she turned in her seat with a narrow-eyed look. "Are you trying to kick me out so you can throw a party?"

"Nah," he shrugged. "But it just hit me you're like, eight-" "thirteen" "-or whatever and you never get in trouble for trying to stay out past curfew or ditch school to go to the arcade."

Nanako stared blankly at her dark haired cousin, wondering despite the obvious familial similarities between them, how they were related. "Do you _want_ me to get in trouble!?"

"No!" he shouted back. "Your mom would kill me and they'd never find the body!"

"Then what do you want?" she demanded, past the point of irritated as the clock ticked a little too close to the time she was supposed to have finished her worksheet so she could watch anime.

"I dunno," he admitted and harshly ruffled her hair. "Just thought it was weird."

She turned her back on him and pointedly refocused on the last three problems in front of her. He rummaged around in the kitchen for a moment then placed a can of soda at the edge of the table and walked off with his haul of _her leftovers from Inko-oba's dinner last night_. She quickly debated throwing her pencil at him then pushed the thought away; she couldn't waste the time it'd take to throw it and pick it back up plus deal with whatever retaliation Kenta came up with.

Club day at the start of the new school year was a perilous time for Nanako. Colorful flyers were shoved in her face and loud cheers assaulted her ears as she struggled to wade through the slow crowds on her way to class. The representative from the cooking club nearly broke her nose with a serving tray full of tiny finger foods then one of the tennis club member clipped her arm with a racket and left her a lovely bruise just above her elbow.

She stumbled into class and turned her quirk inward until her frazzled nerves calmed. Homeroom began soon after, further helping her to settle. The hours of relaxing were for naught, however, as the hounds of hell descended upon her with brutal efficiency-

"You look like you have strong arms, Hayashi-san, you should join the tennis team!"

"No no, the bento you bring are always super cute so you should join the cooking club!"

"Ah, but her math scores are really good so the math club would be best."

Nanako grabbed her lunch and snuck out while they argued. It was well known in her class that she (and a small handful of others) were part of the Going Home Club, which was the cause of a fair bit of ribbing from her friends and (now) flattery (?) from classmates who were trying to recruit.

She made her way up the stairs and settled in an unused hallway. Dust motes floated playfully in through sunbeams. The ruckus of the school was distant and faint, like running water in a forest. She took a deep breath, held it, and felt her body untense as the ambiance worked its magic.

"Hey, do you wanna jo-"

She shrieked.

* * *

 **A/N:** It gets dark at 4pm now, what is this?! Hope you lovely readers enjoyed, and if you did, please leave a review! Internet is kind of spotty at the moment but I read them all and it's the literal highlight of my day!


	3. Chapter 3

**A/N:** An omake/extra scene from Bakugo's POV that takes place the day after chapter one. Dedicated to chibi-no-baka who wanted to know if Nanako would in fact beat someone up for Izuku and also baby Katsuki.

* * *

Katsuki returned to school the day after a doctor's appointment to a boring bit of gossip- Deku had an older sister.

He knew, of course, (not that he wanted to but the rambling idiot never shut up so it came up once or twice) that he had an older sister named Nana. That wasn't even close to being exciting news to him. Though he'd never met her, in the same way he'd never met the other boy's dad, he knew she must have existed because sometimes the crybaby came to school with sloppy All-Might themed bentos that didn't taste horrible (but weren't all that good either).

The only thing that was remotely new or worth his attention was the fact that she looked a lot like Deku- which meant the report of an older student knocking out Akito was about her and not some upperclassman no one could seem to name. Reports varied, because no one had anything better to do than flap their gums, but certain parts had stayed constant.

One: The older girl (who sounded like Deku's big sister given the wild black hair) asked Akito where the vending machines were and said she had a really bad sense of direction, so if he could walk her there she'd buy him a drink from the machine.

Two: On the way, Nana knocked him out… somehow. She then woke him up by pouring milk over his head and told him it was bad to take other people's things. All of Akito's stuff had also been drenched in milk, save for a few items that were missing outright and later turned up in the school's lost and found.

Though it wasn't mentioned when the story was told and retold all those weeks ago, and Akito would never fess up to stealing other people's things, Katsuki knew that Deku's missing Hero Journal had mysteriously been recovered around the same time. He'd figured the two weren't related on account of the fact that the idiot found the notebook in the library tucked behind an atlas of all things, but now that his sister had been identified his brain had made the connection between the two descriptions.

Obviously his sister hadn't been cursed with quirklessness like Deku was, and whatever quirk she did have _must_ have been decent at the very least if she was able to knock someone out and keep them out long enough to finish out the rest of her plan. Still, the question remained about _what_ quirk she had and while he could have easily pummeled the answer out of her useless brother, he wanted to meet her face to face and find out for himself.

To that end, he stuck around school one day until he saw the crybaby leave with an older girl then he followed until they were a little ways away from the school.

"Oi Deku!"

The wild-haired pair turned to look at him in an eerily synchronized motion. Deku had a dumb grin on his dumb face, but that wasn't what he was focused on. The useless boy's older sister was wearing the uniform of the local private middle school, though he didn't know the name of the place, and had her hair up in a ponytail. Nothing about her looked out of the ordinary, no obvious muscles or unique coloring or cool accessory, and for a half-second he doubted she even had a Quirk but his brain wouldn't let go of the odd connection between her and Akito.

"Do you know him, Izu-kun?" she asked and raised an unimpressed brow.

"Yeah, it's Kacchan!" he exclaimed and scurried closer rather than make the other boy keep walking to meet them. "Hey! Did you want to hang out with us? We're gonna get parfaits from the café by-"

"You talk too much- shut up," he groused then turned his attention to the older girl.

She was already looking at him, sleepy eyes narrowed and sharp, with a pull to her lips that reminded him of his dad after a long day. "Can I help you?"

"Yeah, what's your quirk?" he demanded. "How did you knock Akito out for so long?"

She hummed. "You must have the wrong person- I don't know anyone named that."

He scowled. "Whatever- just tell me what your Quirk is."

"Why?" she shifted her weight to one leg.

"'Cause I wanna know!"

"Why do you want to know?" she drawled.

"Just tell me!" he shouted. Did she have to be an irritating dumb ass like her brother?!

"No thanks," she pulled out her phone to check the time. "Ah, we're going to be late- let's go Izuku."

"No way!" Katsuki stomped forward. "Why won't you tell me- I bet it's a lame-ass quirk anyways!"

"You're annoying," she sighed and crossed her arms. "Fine, you know what? I'll tell you if you can beat me in an arm wrestling contest."

He perked up. She was as big of an idiot as her brother to propose that- his quirk was going to _demolish_ her. "Fine, you're on!"

"Great," she started walking away. "Me and Izuku are going to a café so follow us and we can do it there."

"I don't follow anyone," he rushed ahead.

She didn't say anything, just walked on, but then she took a turn he wasn't expecting and from there he had to watch which way her body turned out of the corner of his eye so he could pre-empt her and continue to lead. When they arrived, he scrunched his nose in disgust at the flowery décor. Of course she and the crybaby would pick something as girly and frail looking at this place- but he wasn't planning on staying long so he pushed his annoyance away and entered with only faint complaints.

Irritatingly enough, she insisted on ordering first, which took forever, and when she finally picked a seat she _had_ to sit at one of the two person tables that barely fit the three of them.

He threw his elbow onto the table in a ready position and she shook her head- what now?!

"Best two out of three," she said and planted her arm on the table with her palm upright and facing her. "Izuku's the referee and the first round is American style."

"HUH?!"

"You wanted to know my quirk, right?" she waved her arm in place. "So either beat me twice or live without knowing."

He huffed and mimicked her weird ass set-up, then Deku called start and he yanked his arm with all his strength. Her grip easily gave way and he smacked himself in the mouth before slamming his hands on the table as he stood. "You cheated!"

"Your hand hit the table," she rebuffed. "It's not my fault you don't know American style arm-wrestling."

"I want a do-over!"

"Why?"

"BECAUSE YOU CHEATED."

"I don't think so, but- ugh, look, why don't you decide how we play the next round? Will that make you feel better?"

He wanted to punch her in the face but even cheating dumbasses had a point- there were still two rounds and even if she won once there was no way he was going to lose the next two. "Whatever!"

He readied his arm, she matched, and a scant second after Deku gave the signal he slammed her hand against the table with help from his quirk. She winced and massaged the area.

"Okay, next we should do left handed-"

"Why, so you can cheat again?!"

"How is left-handed cheating?" she asked. "I'm right handed and you're obviously pretty strong so it shouldn't hurt you to try."

He couldn't find a way to argue aside from accusing her of more cheating. They set up for the third time, Deku said start and-

Katsuki woke up to see that Deku and Nana had finished their parfaits. He shot up and pointed an accusing finger at Nana. "YOU CHEATED AGAIN!"

"How?" she asked with a smug smile. "You used your quirk to win- so if I cheated by using mine then you cheated too."

He was shaking with rage but couldn't put it into words. She didn't seem to care, relishing the pastry she'd apparently ordered while he was knocked out, then stood and waved over her shoulder.

"See you later," she called. "Don't forget to eat your food."

He turned to snap at her but saw the chocolate coronet on a napkin set off to the side and instead shoved it in his mouth angrily. One of these days he was going to kick her ass, mysterious quirk or not!

* * *

 **A/N:** Hope you lovely readers enjoyed! I had a lot of fun writing this :) Bakugou shows up in the next chapter too, so look forward to that!

See you next week!


	4. Chapter 4

Izuku stared at his dark-haired neighbor as she rolled a pencil between her fingers and glared at the paper in front of her with uncharacteristic heat.

"Uh, Nana-neechan?" he queried and gently poked her shoulder. "Are you okay?"

She turned, eyes flashing with pent-up anger. "No."

"Oh…" he discreetly leaned back. This was a look he knew well. "Do you… wanna talk about it?"

Her frame tensed for a brief second before she blew out a long breath and slumped forward. "Yeah sure I guess." She pushed her paper away and settled her head on her arms, facing him.

"Kenta-nii and me got into a dumb fight the other day, and he left in a big huff so I didn't really care when he didn't come home the whole night," she seemed to deflate a little before his eyes. "Then I found out that someone tried to mug him. They broke his arm and ran."

"Oh no," his eyes filled with sympathetic tears. "Is he okay now? Did you guys make up?"

"Sorta," she shrugged. "He had to get a cast but he wasn't hurt aside from that. He told me not to worry about it and that it wasn't _my_ fault, but I still feel really bad…"

"I'm sorry," he wasn't sure what to say.

"Yeah, me too," she sighed heavily. " 'Specially now since my mom's making me sign up for self-defense classes." This after she had narrowly dodged getting dragged into joining a club by her friends and classmates…

"Your mom?" he tilted his head curiously. "What's she like? I don't think I've ever met her."

"You haven't. She's… hm," Nanako dug into her pocket and pulled out her phone. "Well, I look kinda like her except my hair is crazier. She's a really famous surgeon or something so she works overseas at a fancy hospital."

She angled the screen his way to show a woman with straight black/brown hair wearing green scrubs standing in front of an operating room. She had Nanako's sleepy sage green eyes and wide mouth, but together it looked more severe on her face than on her daughter's. The next picture was the same woman, but wearing a dress and smiling.

"Wow, she's almost as pretty as you," he said without thinking.

She reddened and yanked her phone away. "Mn."

"What's her name? Why does she work so far away?" he searched her face for more similarities but couldn't find anything more concrete. "Is she nice?"

"I mean, I haven't really seen or talked to her much since I moved here," she stared at the woodgrain beneath her arms. "She was kinda strict when I still lived with her, but not mean or anything- so, yeah, I guess she was nice? Not sure why she moved so far away for work. Her name's Akemi."

He nodded. "Does she like All Might?"

"Doesn't everyone?" She sat up. "But even if she does, you don't have to worry about her taking your spot as his #1 fan or anything."

His eyes darted over to his All Might themed sneakers that were lying by the door. "… Do you think she could do that? Would she?! What if she's already met him and they're super best friends!?"

She laughed and ruffled his hair. "I doubt that, Izu-kun."

"But what if?" he pressed and felt a wave of calm overcome him.

"How about we bake some get-better-soon cookies for Kenta instead of making up conspiracy theories, hm?"

He smiled widely at the prospect of getting cookies in the near future and jumped to his feet. "Okay, let's go!"

 **-[-]-**

Self-defense class was hell on earth. Not only was Nanako the youngest in the class, but she also showed up in her gym class uniform while the older, more confident students were decked out in designer brands or outfits that emphasized the best parts of their shapes- unlike her baggy t shirt and clingy, too long shorts that made her look like a blob balanced on two chicken legs.

When Kenta came to pick her up after class, she threw herself at him and begged never to go back. Her cousin, of course, was unsympathetic to her frantic pleas but took her to buy cuter workout clothes and promised her that if she stuck with the class he'd convince her mother to let her get a new laptop. Otherwise, if she didn't give it a real effort he'd tell Inko-ba that she didn't want to learn how to _protect herself_ , and the woman already looked like she was going to burst into tears whenever she saw his broken arm.

"You're evil," she frowned over her soft serve ice cream cone.

"Yeah sure," he took a sip of his milkshake. "Just take the class seriously and you won't have any problems, okay?"

She grumbled but when she walked into the next class on Thursday she did as he said and it was slightly less terrible. Still bad because she didn't know how to throw a punch and her default response to being grabbed suddenly was to either freeze or slump like a rag doll, but less terrible. She made a few kind-of friends with the older ladies in the class by the third week, which helped a lot since they were as clueless as her.

"Oh, my little Chiyo was so concerned when she heard the bank next door to my work had gotten robbed," Eri-san said between sips of lemon flavored water. "She showed up at my house with a list of local dojos a week later and had this big, passionate speech about how dangerous it was to not know how to defend myself- it took her forever to get through and it was obvious she'd thought a lot about it… Still, I didn't have the heart to tell her I'd already signed up for this class!"

She laughed with her whole body and Nanako found herself giggling along.

 _-0-_

"Alright now, you've gotta stand like this," Nanako demonstrated. "And twist with your body like _this_."

Izuku mimicked her as best he could and nearly fell over.

"Woah, not that much!" she fixed his stance with a few quick tugs when he found his balance. "And hit _out_ , like your fist is going through the pillow."

He tried again and it was better.

"You got it!" she exclaimed. "Now we can move onto kicks. It's really important to…"

By the end of the eight week course, Nanako could break a chokehold, get free from being picked up, and a whole host of other things she didn't think would be possible when she first started. True to his promise, Kenta-nii got her mother to agree to let her get a new laptop and she was over the moon when the sleek, matte black computer flickered to life under her hands. She quickly transferred over any important files from her old model onto the new one then stayed up until two AM playing random games.

She woke up four and half hours later to get ready for school and wanted to die.

 **-[-]-**

After a day or two to adjust back to a normal sleep schedule, Nanako felt less like a zombie and more like a human being again. As a reward, when Kenta and Inko-bachan went grocery shopping she hopped on her new (!) laptop and started an account for the MMORPG her classmates had been gushing about.

Izuku became curious about what she was doing and stuck his face in the middle of her screen after twenty solid minutes of her clicking around like a madwoman. "What're you doing nee-chan?"

"I'm playing a game," she tried to angle the screen to see past his head of wild hair, but his curls were as bad as her waves and that failed. With a huff, she elbowed him and made room on the couch so he could sit next to her. "Or rather, I'm going to play a game but I gotta make my character first and I can't decide what kind to make."

"You should make All Might!" he exclaimed and gasped when she somewhat followed through on his suggestion. Her androgynous cat person became a tall, strong man with a healthy tan and blond hair.

"Ah, but I think making someone exactly like him will cost money," she grumbled as she eyed the golden outline around the All Might customization options. She hovered over the box with his same hair and scrunched her nose at the price that appeared. "See, even something little like this is expensive."

"Oh," he frowned. "Well… I guess you could make your favorite anime character?"

She hummed then slapped a smattering of freckles onto the avatar and changed the blond to black with green highlights. He squawked and nearly leaped face first into her laptop.

"THAT'S SO COOL!"

Nanako adjusted the muscle slider and snickered when he made a wounded noise at how scrawny his character looked. With a little more tampering, it started to actually look like _him_ and not just a dark haired man with freckles. They got as far as selecting a race before she had a lap full of Izuku and couldn't see the screen anymore.

"You wanna try?" she pointedly moved the computer away.

"Yeah yeah yeah!" he vibrated in place.

She set the laptop on the coffee table and went to fetch her old one from its spot in her closet. It had been almost completely wiped so there was plenty of room to download the game's demo and Izuku threw himself into the character creation wholeheartedly. By the time their older counterparts had gotten home, he had a folder full of screenshots of the many pro-heroes he had tried to recreate and Nanako was walking him through what the steps of the scientific method were so he could improve his Hero Analysis notebooks.

Said notebooks were spread across the table as reference and the scene reminded Inko strongly of working overtime with the company accountants at the end of the fiscal year. Kenta, on the other hand, was reminded of the midterms he had coming up and slunk away to his room to avoid responsibility.

"Mom, Mom, look!" Izuku pointed excitedly at Nanako's laptop screen. "Nana made you!"

She looked at the screen and pursed her lips to avoid bursting into laughter. "I see."

Game!Inko was slender with a generous hourglass shape and skimpy clothes. She had the same hair as real Inko, though it surrounded a considerably more pouty and seductive face. Still, her crop top _was pink_ and the floor length skirt (with _very_ high slits) _was dark blue_ which matched her current outfit of a pink sweater over a dark jean skirt. A game like the one they were playing probably didn't have normal clothes or average features; they did the best they could, she assumed and nodded appreciatively.

"I take it you two had fun?" she glanced at the quietly arguing pair as they went back and forth between two similar hairstyles for a character she guessed was supposed to be Kenta-kun.

"Lots!" Her son cheered while Nana-chan nodded.

"Hm, then I suppose I ought to get you this game…" she trailed off mischievously. "Or we could get that new All Might figure that's coming out next month."

"REALLY?" He gaped dramatically then barreled into her legs. "ALL MIGHT ALL MIGHT ALL MIGHT!"

Inko chuckled to herself and nodded along as he gushed about the number one hero; it wasn't even a contest.


	5. Chapter 5

**A/N:** Though nothing explicit happens, and there is NO assault aside from hand touching and an arm grab, TW for pedophilia. It's more so focused on how creeped out Nanako feels, but still- keep yourselves safe out there!

* * *

Nanako's second year was going mostly well. She'd scored in the top twenty percent of her class for all the end of winter tests, her practice high school entry exams had also gone well (though she needed a little work in English) and Kenta-nii promised to take her on a trip if she ended the year with equal or better scores. On the social side of things, she'd managed to make a new friend and her other friendships had progressed to the point that she regularly went out on the weekends, which Inko-oba greatly enjoyed seeing as Nanako went to her for help with hair and clothing seven times out of ten.

There was just… one problem…

"Ah, good job Hayashi-kun," Sugimoto-sensei said as he handed back her history paper. "I see you used those reference books I recommended." His hand lingered on hers a touch too long.

"Mm," she hummed and kept her averted. "They were helpful."

He moved on, quickly handing back the other students work with a comment or two thrown in for exceptionally good (or exceptionally bad) papers. The lunch bell rang soon after and she was surrounded on all sides by friends and a few giggly classmates.

"Wow, I wish Sugimoto-sensei would recommend me books!"

"Ah, he's so handsome!"

"And smart!"

"Do you think he'd accept chocolates from me for Valentines?"

"Don't be dumb- there's no way he'd go for someone as plain as you!"

She laughed along as they continued to squabble, slowly getting their lunches out and breaking into smaller groups. Sugimoto-sensei was fairly young, kind, and good looking, so almost every girl in her class had a crush on him. The boys, of course, grumbled about that but aside from their teacher giving slightly more praise to the girls, there wasn't much to complain about.

Nanako, on the other hand, wished he was ugly, dumb, mean, and bad at teaching so everyone would band together to get him fired.

It wasn't that he'd done anything _overtly_ wrong, but he gave her the creeps and always seemed to pay a little _too much_ attention to her. Case in point, she'd worn her hair down one day in tame waves and he'd twirled the end of one dark lock between his fingers.

"Your hair looks very cute today," he said with a kind smile. "You should wear it like this more often."

She nodded, thanked him politely, then never wore it down at school again.

There were other things, like how concerned ( _interested_ ) he was about her home life, but each individual thing was so small she felt like she was overreacting. Confiding in Tomomi, her most level-headed friend, hadn't done much to dispel that notion either, so she dropped the subject and focused on something less likely to drive her crazy- bribing Raido with a week's worth of snacks so he'd fork up three tickets to Hero-con, for one.

 **-[-]-**

By virtue of being the oldest, Nanako was the designated "group leader" on their trip to Hero-con on bright Saturday morning. Of course, she was only fourteen to Izuku's and Katsuki's ten so the loud mouthed blond protested that decision, but his mom only needed to knock him upside the head once and yell about him being ungrateful about being invited along to a sold out event for him to grumble and relent.

That settled, they waved goodbye to Inko and Mitsuki-bachan (Nanako had tried to call her "Bakugo-san" and gotten an earful for it). They joined a line that stretched around the building meant for those who already had tickets, which was half as long as the one for people without passes, but it was still a long wait. To pass the time, she handed Izuku his DS and stuck in her earphones so she could find something to watch.

Not five minutes later, she realized Katsuki literally hadn't brought anything aside from the clothes on his back (and maybe his wallet) judging by the bored look on his face as he glanced around at the other con attendees in line. On top of that, she was almost certain that he hadn't eaten breakfast before being shoved out the door by his mom- or if he had, it hadn't been enough because he was eyeing some kid's melon bread a little too intensely.

She dug a chocolate chip muffin from her backpack and made a mental note to stop early for lunch.

"What the hell is that?" he sneered at the treat when she held it out.

"Bread and chocolate," she waved it more in his direction. "You're hungry, aren't you?"

He looked like he was going to smack it out of her hand, but then Izuku looked up from his game with a happy cry of "A chocolate muffin!" and then he _had_ to deny him the opportunity. In the time it took her time to blink, he snatched it, ripped open the plastic packaging, and shoved half of it in his mouth.

"Piss off, Deku," he spat out a few crumbs and swallowed loudly. "This is mine!"

Undeterred, Izuku turned wide, hopeful eyes Nanako's way and was rewarded with his own treat.

"Ugh, you're always copying me," Katsuki polished off the rest of his snack.

They shuffled forward a few steps.

A baby started crying some distance away. A woman strolled by in a meticulously crafted cosplay, complete with four inch platform boots and a war hammer as tall as she was. The doors weren't set to open for another forty minutes.

"What are you playing, nerd?" he jabbed his elbow into Izuku's side not ten minutes later.

Nanako rolled her eyes and increased the volume on her phone. It was going to be a long day.

 **-[-]-**

It was, in fact, a long day and she had to snag Katsuki by the collar several times to make sure he didn't start brawling when traffic in the artist alley crawled to a near stop. She would have held his hand like she did for Izuku, but the blond had violently ripped his arm away from her when she did and ended up stumbling into people, which only made the traffic worse. At one point someone had run him over on their way to take a picture of a cosplayer and she'd loudly chastised the offender, though he didn't seem to appreciate that either… He didn't care for the panels, but he and Izuku both lit up like a sky full of fireworks when they came across the booth for the official All Might fan club, which was adorable.

"Wow, he sounds like a total tsundere!" Sayuri exclaimed between bites of lunch.

"More like all tsun and barely any dere…" Tomomi pointed out.

"He's only ten," Nanako shrugged. "I'm sure he'll calm down when he gets older or something."

Her friends exchanged a sly look then turned their sharp gazes at her. "Brother complex!"

"WHAT!" she choked on her apple juice.

"Admit it Nana-chan," Sayuri teased. "You have a little brother complex!"

"No I don't!" she denied with a vehement hiss, glancing around to make sure no one else was paying attention. "Don't say that!"

"The first step to overcoming a problem is admitting you have one," Tomomi nodded wisely.

"I think it's cute," Sayuri swiped an orange slice from Nanako's bento. "And you're like, perfect for the part of a Cool Big Sis!"

"How," she sighed. If anything, she saw herself as an ideal Little Sister what with her devotion to making sure Kenta didn't starve or go crazy for as long as they'd lived together. Even his friends had jokingly called her an angelic little sister when she did things for them without being browbeaten into it.

"Well, when you nearly bit that photographers head off for smacking into Katsuki for one."

"And that time you stopped in the middle of delivering papers to the teachers' office to help that one underclassmen who'd spilled paint down his front."

"Or that one time when we went to the mall and you helped that girl find out where her friends went even though there was that huge sale going on at Icy's."

"Also when-"

"I get it!" Nanako buried her blushing face in her hands. Okay, so maybe she did have a problem with taking care of anyone younger than her… but did they have to bring up so much detail to prove their point?!

 **-[-]-**

Once again on cleaning duty, Nanako texted Izuku to let him know she'd be a later than usual and carried the stack of handouts to the teachers' office. The class rep typically handled the paperwork, but Yoshida-kun was going in to get braces so he'd asked her to do it. In return, he would talk his friends into letting her join their guild for the Midnight Caverns event that was going on next week.

The room was empty, aside from all the teachers' stuff, so she quietly excused herself and walked in. Tsukuda-sensei's desk was the one closest to the back corner and decorated with a tiny American flag alongside the framed photo of her and her spouse.

Nanako set the forms on her desk then felt her heart leap into her throat when Sugimoto-sensei's face peeked over the edge of his desk.

"Ah, I thought I heard someone," he got up from the floor. "Good afternoon Nanako-kun."

"Good afternoon," she responded politely.

"Say, you know a lot about computers right?" he ran a hand through his artfully tousled hair.

"A little," she resisted the urge to fidget.

"Great!" he clapped his hands together. "I was having a little trouble with my computer screen…"

Against her better judgement (Tomomi had said she was overreacting, after all), she went over to help him and found herself tucked under his arm as she fiddled with the cords that connected the monitor to the computer. When the screen flickered back to life, he breathed a sigh of relief in her ear and clamped a warm, heavy hand onto her shoulder.

"Thanks Nanako-kun," he smiled, too close for comfort, and she felt her stomach clench painfully. "You were a big help."

She nodded, mute as her instincts screamed at her to _run_ , and walked out.

 **-[-]-**

Valentine's Day was a Big Deal, even at a science-focused middle school. While Nanako didn't have a crush on anybody, she did have friends, a cousin, and a semi-adopted little brother/neighbor which meant she needed to make a _lot_ of chocolate. Thankfully however, Valentine's fell on a Tuesday so she was able to spend Sunday trying out different chocolate molds, techniques, and recipes.

The holiday dawned bright, clear, and cold but even the winter chill wasn't enough to dampen her mood. With her long hair nicely done up and a cute bag filled to the brim with even cuter treats, she walked Izuku to school then made her way to class. When she walked in, there was a buzz in the air, a sort of nervousness she could feel in her teeth that buzzed in the back of her head if she focused.

It was annoying.

She scrunched her nose and took her seat, then used her Quirk to subtly lower the level of anxiety permeating the room. That accomplished, she dialed back her reach and focused on keeping only the area immediately around her calm- if she overextended herself for too long she'd turn into an emotionless zombie who couldn't recognize her own hands and that would suck.

Classes went by quickly, and so did lunch. Her bag of goodies was a hit, both because they tasted good (she sent silent thanks to Inko-bachan for the help) and because she had hero-themed treats. Raido, who she hadn't even made chocolate for, was especially over the moon when he begged an All Might shaped one off of Sayuri and found that it was painted (with colored white chocolate) to mimic the #1 hero's costume.

Izuku, she knew, would be equally over the moon when she finally gave him his, but first she had to contend with cleaning duty…again. It was a stroke of bad luck to have been assigned to it so soon after her last stint, but she probably wouldn't have it again for the rest of the year which was a welcome thought. Having to stay after school to clean up other peoples' messes so close to finals was a stress she didn't mind avoiding.

She dumped the trash off at the dumpster, then scurried back to class to retrieve her school bag. There were two people still in the class, red faced and radiating with intense nerves. She hurried out and took a deep breath to clear her head at the top of the stairs. Her own calm restored, she strolled down the steps, past the many classrooms to the shoe lockers to change into her sneakers and stood to leave-

"Ah, Nanako-kun," a familiar ( _bad_ ) voice called and a heavy hand wrapped around her wrist. "There you are."

"… yes?" she glanced through the glass doors at the front gate of the school with longing for a split second. "Sensei."

Sugimoto-sensei lifted her arm and the cutesy bag dangled between them. "I meant to tell you earlier, but it's against school policy to bring food like that for other students unless it's store-bought. There are concerns about that sort of thing with the school board, you know?"

Why the hell was he telling her now, just as she was about to leave for the day?

"Sorry," she said without feeling.

"I'm sure you will reflect seriously on this for the future," his other hand came up (her heart clenched in anxiety) and he took one of the small plastic bags. Specifically, he took the one she'd set aside for herself, the creepy goddamn _jerk_.

Ignorant, or uncaring, of her displeasure, he smiled widely and continued, "But sensei will let this go in exchange for a little treat, okay?"

"Okay," she slowly pulled her arm out his grip. She turned on her heel to leave and he followed, opening the door for her and keeping pace with her shorter strides down the long (gods, was it always this long?) walkway to the front gate.

Respect for elders and all those other polite lessons her mother drilled into her be damned, Nanako had a _terrible_ feeling just from being this close to him and was half a second away from flaring her Quirk in the hopes that he'd pass out.

The nerves in her stomach had coalesced into one leaden knot as they approached the last few feet- would he try to offer a ride home or walk with her or-?

"Nana-nee!" Izuku's excited voice called out and all the tension in her body evaporated.

"Izu-kun!" she called back then, "Oh, and Katsu-kun too?"

(Sugimoto put a few feet of distance between them and walked off, simmering and silently frustrated.)

"I told Kacchan that you made All Might chocolates so he came to get some too," he explained and bounced on his heels as she drew closer. "You didn't eat them all, right nee-chan?"

"I didn't," she replied with a smile and inclined her head Katsuki's way. He wasn't looking at her, instead staring at the retreating form of her teacher.

"Who was that old bastard?"

She was torn between chastising at him for cursing and bursting into laughter.

"That was my history teacher," she choked out and pressed a hand to her mouth to keep her giggles from escaping.

"He looks weird," he said and swung his attention to the bag on her arm, red eyes sharp.

"Mhm," she pulled out the cutesy plastic bags with pink hearts painted on one side and a solid white background on the other and handed it off, careful to give both boys the treat at the same time.

Her neighbor/adopted little brother lit up with a "thank you very much!" while the blond barely grunted out a "thanks." If it hadn't been for the way his mood peaked with happiness and her own troubling tendency to try and nurture others, she would have knocked him out with her Quirk for his barely polite gratitude.

"Oh, did you give your sensei chocolate too?" Izuku said and undid the shiny metal twist at the top. "He had a bag just like this."

"N-not really," she nearly stumbled as they started home. "More like he took one…"

"Eh?" Katsuki said around a mouthful of chocolate. "Why the hell did he do that? He's like, super old- he can go buy his own."

"I don't know," she avoided looking back, paranoia slowly rising.

"Peh, whatever," he grumbled and finished off the remainder. "Do you got any more?"

"Yeah," she had three bags left, not counting the rejects she had sitting in the fridge, and handed him one. The boys filled the way home with chatter about some upcoming fieldtrip and it did a fair bit to keep her mind off the weird encounter.


	6. Chapter 6

**A/N:** Continued warning from last chapter (TW: pedophilia mention), though this is focused on moving past that. Also, more Katsuki!

* * *

The Monday after Valentine's Day, Izuku's mom picked him up from school, pale faced and mumbling up a storm. He didn't question it, because she didn't look like she could take a question without bursting into tears, but when they drove straight past the turn they needed to reach Nana's school, he spoke up.

"Aren't we gonna get Nana-nee too?"

His mom pulled over and burst into tears just like he thought she would, then wrapped him in a fierce hug and sobbed incomprehensibly into his hair. (That was never a good sign.) He patted her back like she always did for him, and after a few minutes she was composed enough to drive again. (His stomach was in knots.) Their apartment wasn't very far, and she looked ever more frazzled than before, so he kept quiet until they got in and his mom had the chance to make a pot of tea.

"Kaa-chan, did something happen?"

She nodded, fresh tears in her eyes, and started to ramble almost too quick for him to catch. "Oh poor Nana-chan must be so distraught and all those poor girls- oh! Oh it's so _terrible_."

He felt something hard and heavy wrap around his ribs. "Nee-chan…?"

"Yes," she swallowed down a sob and took his hand (so small in hers). "You see, there was a very bad man at her school… her teacher, at that…"

 **-[-]-**

Nanako didn't go to school for the rest of the week except for Friday. She just didn't have the energy, not even to leave the house, which was a little ironic considering that she spent so little energy every other time that she should have had a mountain of it saved up. But no- the idea of having to walk outside and feel everyone's eyes on her, like they could see the _almost_ crime written on her skin, turned her stomach and drained her of every ounce of vitality she might have had.

Still, she needed to pick up her homework and Kenta-nii reassured her that he would one hundred percent leave class if she needed to leave early for whatever reason, so she bravely wrapped a scarf around her face and pulled on her softest tights when she woke up that morning (internally her nerves were a ragged mess and she was _scared_ at having to go back to school but-

Izuku was over the moon to see her again. Tomomi and Sayuri swarmed her with any gossip she'd missed and formed a two person shield between her and the rest of the class. No one brought up Sugimoto-sensei except to mention how happy they were that he was going to rot in jail for a long, long time.)

It was only one day, but it wiped her out all the same so she took a nap when she got home and Izuku contented himself with playing on her old laptop on the couch until his mom picked him up. Kenta-nii nearly broke down her door when he got off school and didn't see her in the kitchen for her usual afternoon snack, but he did it because he cared and that took the annoying edge off.

She rubbed the sleep from her eyes and stumbled into the living room after him, his pitchy half-panicked voice almost like white noise except for the fact his panic stabbed at her fragile well-being. Before he could work himself up too much and drag her into an equally panicked mess, she wrapped her arms around him in a tight hug and gently pushed her quirk against his frazzled mind.

"I love you too, Kenta-nii," she told him and ignored the fact that he was an ugly crier. When he was done, he sniffed and ruffled her hair so much that she could barely see him.

"Aren't I supposed to be the one consoling you?" his voice was nasally and thick.

She shrugged- heavy use of her quirk had kept her level-headed enough to not break down, though it was a near thing. He wrapped her in another tight hug then sighed and walked to the kitchen.

"I'll order in tonight- you can pick," he called and she relaxed at the thought of not having to go out again.

 **-[-]-**

Nana-nee was a little jumpier for the rest of the school year after her ordeal, but she was also much more affectionate. His mom explained that she might withdraw from things or be grumpier than usual, but she wasn't- except when they were in crowded places. Then, she glared at everyone and made sure to stick close to his side, a hand in his or on his arm or between his shoulder blades but always touching. Her tone grew noticeably cooler with adults (men in specific, though he didn't pick up on the distinction because he wasn't looking for it) but she was still nice to him and made him bentos almost every day.

Her cooking lessons and practice definitely paid off because his lunches went from simple and basic to more elaborate and flashy, almost always patterned after All-Might. As a result, his classmates warmed up a little to him and even swapped parts of their lunch for his. The overall swell in positive attention boosted his mood but had the opposite effect for Kacchan. He thought it was because the other boy didn't have a cool nee-chan to make him snacks and play video games with so he was _jealous_ , but he didn't voice that thought out loud in case his oldest friend decided to make him shut up with his fists. (He did that a lot when Izuku surpassed him in some way, and even when he didn't.)

… Rather, he _didn't_ bring up that thought until one day when lunch was almost over and Kacchan knocked his bento from his hands and called it "ugly crap- not good enough for _dogs_ to eat!" Then he threw the fact in his face and got a right hook to the jaw for it.

They ended up in the principal's office, bruised and scratched up, but unlike most other times, Izuku had given as good as he'd gotten and felt a quiet, unconquerable sense of _rightness_ settle in his gut even as he was made to apologize. That quiet feeling grew stronger when Nanako (alongside her cousin) picked him up and fussed over his injuries while Kacchan had to sit in the corner by himself. It was mean, yes, but he was _right_ and he had something Kacchan _didn't_ for once.

It was a heady feeling.

 **-[-]-**

Nanako screamed into her pillow and tugged at her hair. Her graduation ceremony had been a few short hours ago, followed by a laughter filled lunch with her two best friends, and her mother just had to _ruin_ it.

A transfer? To an all-girls middle school? An all-girls middle school in _Kyoto_? _In her last year of middle school_?! Things had been hard enough transferring _to_ Meiho and now her mother wanted her to leave!?

Another scream built in her throat and she didn't hold back.

What was wrong with her- to demand that Nanako just pick up her life and go to a whole new _prefecture_ just because her mother was "concerned about the quality of teachers" at Meiho?! If she was really so concerned she could have come back to Japan and talked to her about it but _no_ , she was staying in America and instead dictating Nana's life like she was a pet in a hotel and not _her daughter_!

"You okay?" Kenta's voice came through the door, muffled and a little annoyed.

"Go away!" she shouted and shoved her face back into her damp pillow. Who cared if she was disturbing his study time- her mother was trying to ship her away from all her friends.

He grumbled something that might have been "ugh, hormones" but left and only bothered her when it was time for dinner.

 **-0-**

Her mood remained prickly as the new school year started and Izuku tried to soothe her with hugs and pats like she gave to him. He mostly succeeded but sometimes she pulled away and her eyes went vacant in the way they always did when she turned her quirk on too high.

She'd won the argument to stay at Meiho at least for her last year, though she had to join a club to do so. She had to carry pepper spray with her even though Sugimoto had been her teacher and not some random creep on the street. She had to text Kenta-nii when she got home and get a full day's approval before going out with friends.

Because of her club, she walked to school with Izuku and walked home alone, soil caked beneath her fingernails, except on the days that he stuck around to help out. There weren't many of those (gardening was boring to a boy who worshiped heroes and chased after fights like they were going out of style) but she was grateful for the few times that he did.

That summer was as hot and humid as any other and twice as volatile when she argued with her mother over the phone (over an ocean- a continent- several time zones- three years-). It reached a peak when Kenta stepped in to suggest that instead of attending school in Kyoto, she attend the local all-girls school and after a brief shouting session, Nanako gave in… sort of. She agreed to _apply_ to it despite the fact that she had her heart set on a different high school, but that was enough.

She spent a ridiculous amount of time in the school's garden afterwards, tending to each and every plant to the point that the club advisor had to kick her out so they could go home. It wasn't terribly dark, especially since the sun didn't set until something like eight in the summer, but it was late enough that she palmed her pepper spray and set off.

On the way home (well, on the way home that swung by Izuku's school- she'd taken the route by reflex) there was a tiny, almost nothing little park and in that park was one Bakugou Katsuki sitting alone on a bench and staring at his hands.

Which was weird, but she'd recently developed the habit of fiddling with string or her own hair and Izu mumbled to himself when he was deep in thought so it wasn't any weirder than that and she didn't hesitate to change direction.

"Hey Katsu-kun," she called and walked up. "What are you doing out here?"

He glanced at her from the corner of his eye then glared more intently at his hands. "Go away!"

She raised a brow though he couldn't see it. Rude little brat- he was lucky she liked him. "Did something happen?"

"No, now go away," he turned sharply and she rolled her eyes.

Boys.

"Okay, have a nice night," she said and walked off.

"H-Hey wait!" he hollered. "Where are you going?!"

"Home," she looked over her shoulder at him. "It's getting late."

He scowled, an adorable expression considering all the baby-fat in his cute little cheeks, but what did he want from her? To stay and pester him into talking about his feelings when he was in such a mood that he hadn't even said hello back?

"… did you need something?" she tried.

His scowl twisted to something less mean, more unsure of himself and her traitorous heart twinged in response. He looked like he wanted to say something, ask for advice maybe, but his mouth remained stubbornly closed. If it had been anyone else she would have left them there to deal with their problems on their own- it was too tiring to deal with _everyone's_ problems all the time- but Katsuki was an exception. After another few moments of their odd stare down, she sighed.

"Actually, I think I'm gonna grab a parfait or something before I head home," she said and slowly started walking. "I wouldn't mind some company. It is getting kind of dark, y'know."

A few steps later he joined her- or rather, he took the lead and led her to the café. There was only one of note around their neighborhood, and he didn't seem to remember why he knew the place until they'd already walked inside.

"Ugh, this pansy-ass place," he grumbled.

She hummed and elected to ignore his mouth. She wasn't exactly a paragon of good manners and wholesome language when she was upset either (here she made a mental note to apologize to Izuku with a batch of All-Might themed cookies).

They ordered and sat at a booth (no use bringing up a sour memory), a comfortable silence between them. The vinyl seats was cold beneath their legs as the air conditioner worked overtime, but it was a welcome change from the heavy, humid air outside.

Nanako flashed a polite, closed-mouth smile to the waiter when he brought their snacks and it wasn't until she'd picked up a long spoon to dig in that Katsuki noticed all the dirt.

"Did you get in a fight?" he demanded.

"No," she said. "I'm in the gardening club."

He deflated a little.

"It sounds boring, I know," she nodded. "But I like it. Funny enough, there's a plant in there right now that reminds me of you."

He stared blankly at her with a mouthful of parfait.

"One of the _sensei_ brought it in," she carefully did not flinch when she forced out the word (Sugimoto didn't get to ruin the title for her). "She had it for a few weeks, a housewarming gift from a friend, but then it started dying so she donated it in the hopes someone could save it. It's a dracaena, which means dragon, I think, and the leaves are spiky like your hair with red edges- like your eyes."

She wasn't used to being the one to carry conversation, and it probably showed.

"It sounds dumb," he said.

Well, gardening wasn't for everyone. She shrugged and busied herself with eating. He didn't pick up the conversation so she let it go and basked in the cool, quiet of the café. They left shortly after, parting ways rather one walking the other home.

(A month later she ran into him again and they trekked back to her school to pick up the house plant she'd talked about. He didn't overtly mention that he wanted it, but he _did_ mention it and she could read between the lines.)

Katsuki never did tell her what it was that bothered him.

* * *

 **A/N:** Finals are killing me but here you go! I may or may not go on a short break for Christmas/New Years. This story is pretty easy to write once I get the right plot thread going, so I might just throw out an update for the holidays, but I suppose we'll just have to see! (For those who're interested in RWBY or just want to read more of my works, I have several fanfics about that to tide you over, most of which are also about OCs.)

If you have any ideas/things you'd like to see, feel free to drop it in a review. As evidenced by the omake, I'm pretty open to suggestions (but no guarantees). I have to confess I've been pretty tempted to skip to canon and have Nanako meet All Might, but a long winter makes the spring sweeter and all that!

Hope you lovely readers enjoyed :)


	7. Chapter 7

**A/N:** I am not here, you did not see me. (Bakugou omake part two: electric boogaloo)

* * *

It was weird that for all the years Katsuki had known Deku's loser ass, he'd never met the other boy's dad. He vaguely recalled asking (interrogating) him over it once upon a time, but clearly the information wasn't important enough to stick in his head. And really, it wasn't relevant because he never went over, had Deku over or, y'know, cared.

(Except, a tiny hidden part of himself argued, he did, sorta. Not so much about the nerd's dad, but about his sister. His sister that had been absent for years until recently. The same sister he was dead sure had knocked out Akito in third grade then tricked him into hitting himself in the mouth with an arm-wrestling contest weeks later.)

Which led him to now, sitting at the dinner table while his hag of a mother wiped her eyes and his dad slammed a fist into the center of his chest to clear his airways.

"What?" he snapped and shoveled another bite of rice into his mouth.

"Where the hell did you get that idea, brat?" His mom choked out between laughs.

"Well Deku's hag of a big sister didn't come around until like, third grade-"

"I'm sorry, who's what didn't come around until third grade?" His dad rasped with a smile (weirdo).

"D- Izuku's sister-"

"Kid, Izuku is an only child," his mom shook her head, still laughing like a hyena.

He heard a record scratch shatter his train of thoughts. "But... Wait, then why did YOU tell her to call you 'ba-chan' instead of 'oba-san'?!" He demanded.

"Well she's a hell of a lot cuter than you," she ticked up a finger. "She was nice enough to babysit your brat self at Hero-con without being bribed, Inko-chan basically adopted her..."

Katsuki's palms started sparking as tiny explosions went off. "If Nanako's not his sister, then what IS she? His cousin?! His extra-dimensional twin!?"

"She and her cousin, Keiji or something, are neigh-"

"BULLSHIT!" His hands exploded in full, ruining his bamboo fork.

"Tone." His dad side-eyed him and Katsuki ducked his head with a grimace.

"There's no way they're just neighbors," he insisted and really, it was impossible. Not only did they look eerily similar, Inko-ba-san doted on the older way more than being neighbors could explain, and Deku's useless self was practically leashed to her side when he wasn't running after Katsuki or hero fights.

"I dunno what to tell you, Katsuki," his mom sighed. "At best they're distantly related and they just don't know it, but that doesn't change how damn cute Nana-chan. And polite. And not loud."

He had no comment for that except to gobble down the rest of his food and excuse himself from the table. Tomorrow- tomorrow he would get answers, dammit!

 **-0-**

Katsuki threw himself into his seat and waited, legs poised to launch him across the room at the first sight of Deku's green hair. There he stayed, waiting, until the bell rang and it became clear that the loser wasn't going to show up. He swung around to face the front and brushed off the second-rate extras that tried to ask him what he was looking for.

Lunch (food bought from the cafeteria, not a neatly tied bento like some damn people got) came and went. Classes dragged on. One teacher tried to call him out for not paying attention, but he'd finished the "challenge" problem already and his answer was right so there.

Eventually, school let out. Of course, he had cleaning duty, which he finished promptly (spitefully, his classmates might say, but fuck 'em he had more important things to do). Finally, finally he changed shoes and made a bee-line for Meiho Middle School.

The usual assortment of background extras crowded the streets, chittering and chattering about nothing and getting in his way. He rounded a corner with a grimace (some people didn't understand what a shower was and that cologne couldn't cover BO) and shuddered to a halt as a tsunami of peace settled over him.

"Katsu-kun?" A voice said, distantly through the calm. "Ohh, wait, hm..."

Katsuki blinked himself back into awareness. There was a hand hovering over his shoulder and his bag had fallen to the floor.

"You." He said with half the heat he intended.

"Me," Nanako nodded and removed her hand.

There was a prickling at the base of his spine that slithered up through his chest. "What the hell is up with you and Deku."

"Eh?" She cocked her head and her high ponytail went swinging. "What do you mean?"

"He calls you his 'nee-chan' but you're not even related," a little more emotion seeped into his voice with every word.

"Yeah...?" She frowned; wide mouth made wider by the act.

His cheeks puffed with an aggrieved sigh. (She wasn't related but she was just as damn dense as the loser!) "Why did you lie about it then?!"

"Uh, this is definitely not a five minute conversation," Nanako looked around. People were staring, but what did he care? "Why don't we go back to your school so I can pick up Izuku's homework, and I'll explain after, hm?"

He glared mistrustfully.

"I'll buy you a parfait," she added.

Well... free food was free food. He nodded and picked up his bag.

He led the way back, of course, and didn't even complain when she took too long chatting with a teacher in office. Because he was great like that.

Homework for the quirkless loser grabbed, he (bolted) led her to that shitty café she liked and sat (threw) himself at a booth while she ordered.

"Alright, spill it, witch."

"Tch, I should knock you out for that," she rolled her eyes but failed to follow through. "Anyways- so it's kind of a dramatic story but basically our dad is a two-timer." Katsuki felt the world fall out from beneath him. "He cheated on my mom with Inko-ba-chan, but she didn't know and thought he was a foreign salaryman. Then, once Izuku was born, he 'went back to work' with promises that he'd call and hasn't been heard from by anyone since."

"I fucking knew it," he hissed, palms cracking with a dozen mini explosions. "I knew there was no way you two freaks weren't related!"

"Wow, someone is being real polite for getting a free meal," Nanako deadpanned.

"Whatever." He hmphed. "You can't tell me that mumbling thing Deku does isn't weird as hell."

She shrugged and accepted the peach parfait the frowning waitress held out. She also took his strawberry-banana one and set it in reach, not that he cared because dammit he was RIGHT!

"Anyways, was that all you wanted to know?" Nanako stuck a spoonful of whipped cream into her mouth with a hum.

"I'm going to rub this in that hag's face!" He cheered and plucked a strawberry off the top.

"Ah, now would this 'hag' happen to be... your mom?" She grimaced. (There was something wary in her sage green eyes, but he wasn't looking.)

He scoffed. "She called me crazy 'cause Deku's an only child, but clearly she doesn't know a damn thing. I knew the moment I heard rumors about some weird senpai knocking out Akito that it had to be you, and that you had to be related! No one would go out of their way for some Quirkless nerd unless they were blood family!"

"...Katsuki," she said and grabbed his hand.

He allowed it, only because it was weird, he was curious, and he could explode her hand off.

"Please don't tell your mom that. I lied. About all of it."

The world blacked out.

 **-0-**

He woke up on the couch, at peace with himself. It lasted until he sat up and realized that his pillow was, in fact, Nanako's lap.

"YOU!" He lunged and flopped, face first, back onto her lap when another wave of calm slammed into him.

"This cannot be good for your health," she sighed.

"It's that brat's fault for getting so worked up," his mom laughed. "And yours, for riling him up. Take some responsibility Nana-chan!"

"Yes auntie," she sighed again.

As soon as he could gather the strength, he was going to explode Nana's ugly face... but it was pretty comfy laying here. And the way she ran her nails over his scalp was nice too... NO! NO HE WAS MAD AT HER! FOR TRICKING HIM A SECOND TIME! THAT HEINOUS BI-

"Mm," he melted as she tugged the hair just at the nape of his neck. He could be mad at her later; when she was done groveling for his mercy via head scritches. Yeah.

"I wan' bento," he slurred. He was deaf to his mother's hyena laugh or Nanako's third, heavy sigh.

"Your wish is my command," his living pillow pat his shoulder.

… Yeah, if this was how Deku was treated he could see why the other boy was so damn clingy.

* * *

 **A/N:** This is plot relevant, or will be, for a given definition of plot (j_j)"


	8. Chapter 8

**A/N:** As keen readers might have been able to guess, I've changed up several bits of Japanese culture to fit this fic's plot. (Bento, for example, are only for field trips when you're an elementary student like Deku and Bakugou are at the moment.)

But there's just something so wholesome about having homemade food, ya know?! So that's staying haha

* * *

Nanako was going to drown herself. She already had a plan and everything. First, she was going to go down to Dagobah Beach and climb the mountains of junk there. Then, if the piles of garbage didn't open up and eat her, then she was going to grab the biggest microwave she could and-

"SHUT UP KENTA-NII!" She lobbed an empty eggshell at his big, stupid head.

Her idiot cousin (may the gods curse the day he was born and make him miss his morning bus by two minutes every day) continued to laugh with tears streaming down his face. "You t-tOLD H-I-IM THAT?"

"Stooooop!" she whined. If she wasn't wrist deep in cookie dough she'd go over and beat him up.

He laughed harder.

Stupid. Idiot. _Clown_. Nanako angrily threw the last glob of dough onto the sheet pan and put it in the freezer for ten minutes.

"W-h-" he wheezed "-y did you think th-a-at was a good id-e-ea!" He wiped his eyes.

She groaned and laid her forehead on the counter. In the moment it'd been so funny; how could Katsuki NOT know she and Izuku weren't actually related? It seemed impossible that Izu's oldest friend wouldn't know something so basic! So she played along, ready to admit she was joking the second he questioned it or asked for proof, but he didn't. He honestly believed there was- was some _conspiracy_ or something! That she and Izu would just lie to him for years for some odd reason when she hadn't lied to him about anything before!

(That arm-wrestling contest wasn't a lie, just... uh, a trick, sort of. Technically she hadn't done anything wrong and she would stand by that dammit!)

So, she realized, sitting at that café table in public, that he was not going to take the truth well, and knocked him out.

In. **Public.**

The waitress freaked out and then some other people freaked out and she had to claim he had narcolepsy. The second everyone calmed down courtesy of, uh, common sense and NOT an illegal usage of her quirk, she called Kenta to pick them up. He was on a study date with his girlfriend, but he did.

Then they had to drop Katsuki off and she ended up staying a while to explain things to his parents... so it took all that time until she was able to go home and she promised to explain to her cousin later.

Now it was later (almost 8) and she'd already beaten herself up enough about the whole thing that Kenta-nii's laughter was honestly making her want to cry. She still had to tell Inko-bachan too, which would probably kill her on the spot. She couldn't stand it if her super awesome auntie hating her, could barely stomach the thought.

"I thought it was funny, but clearly _it's not_ and now I have to apologize to everyone," she grumbled.

"Yeah no kidding," he caught his breath. "Oh man, I haven't laughed like that in a minute."

"You're so mean!" Her cheeks puffed up with an angry huff. "No sympathy at all for your cute little cousin!"

"Well it turns out my 'cute little cousin' is a troublemaker," he shot back with a smile. "Ah, and here I was so concerned that you were more grown up than me."

"Like that's hard."

"Ouch, Nana, that hurts," he clutched his chest and staggered back.

He was a senior in university and yet still found it fun to pick on his seven years younger cousin? She rolled her eyes and transferred the cookies into the oven.

"No but really, I was gettin' worried you weren't like, living out your childhood or whatever," he scratched his chin, where the faintest stubble grew. "You know, after Asshat and all that, so I'm actually kinda glad you did this. Proves ya still got some kid in you, or whatever! Also, uh, if you want, I can tell Inko-ba-san for you?"

Now he made her want to cry for an entirely different reason. "No, it's okay. I can tell her myself, but thank you nii-s- uhm, nii-chan."

"Hey! Don't go getting sappy on me!" He turned away, the tips of his red ears visible through his slowly falling apart low ponytail.

"Okay, whatever you say... nii-chan." She chuckled to herself when he powerwalked to his room mumbling about "emotional brats" and "why was I even worried?"

Nanako loved her cousin, even if he was kind of annoying.

With a fond sigh, she cleaned up the kitchen and took the cookies out when they were ready. While they cooled, she finished packing Katsuki's bento and stuck it in the fridge beside hers and Izu's.

Then the cookies were cool. She packed them. It was time to face the music.

She draped her apron on its hook, slid on sandals, and shuffled next door with her heart in her throat. Inko-bachan opened the door and ushered her in with a smile, same as she ever did. There was the scent of dinner and green tea; she must have been unwinding. The TV played softly in the background, a soap opera rerun, one of the less cliché ones.

But Nana couldn't move her foot over the threshold. Every toe was rooted to the concrete hallway. Her neck strained under her sudden ninety-degree bow, arms outstretched with her apology gift.

"I'M SORRY!"

The door creaked. "Nana-chan? Is something wrong? Why are you apologizing?"

She stood back up but couldn't meet her neighbor's eyes. "I, uhm, messed up real bad 'cause I wanted to play a prank on Katsuki."

"Ah," she said, not understanding but patient nonetheless (Nana didn't deserve her).

"A-and I might've said that me and Izuku were, uh, half-siblings but that our dad was kinda... scummy... and cheated on my mom... with you... then left the country..."

It was only years of experience in deciphering her son's mumbling that allowed her to understand the nervous girl in front of her. "I see."

"Just- I dunno!" Her grip tightened on the container of cookies. "I know my mom doesn't know who my dad is or where he's at and I didn't think about Izu or you or how it might sound if I was making up stories about Izu's dad since I don't really know anything about him! I really didn't do it to be mean or anything! I just- I though Katsuki knew and he'd call me out but then it spiraled from there and I'm sorry! I'm really, really sorry!"

"Well," she sighed. "Hisashi did leave the country-"

"Wait, really?" Nanako wheezed.

"Yes, he did," she crossed her arms over her chest. "He didn't want to be a father, but he wasn't going to stop me from being a mother."

And this? This crushing sense of guilt? This was exactly what Nana wanted to avoid. That and the look of old grief across Inko's face was enough to make her tear up. "I'm sorry."

"It's- well, it's not okay," she said gently. "But you didn't know how close to the truth you accidentally were. And you've said you didn't do it to be malicious."

"I didn't!" She squeaked.

"So I suppose all that we can do is accept that this happened, and try to think a little more carefully about our words going forward, hm?"

"You..." Nanako's throat closed. "You don't hate me?"

"Hate you?" Inko's eyebrows flew to her hairline. "Oh, no, not at all Nana-chan! It was a mistake, and you told me about it directly. I could never hate you, especially not over something as little as this."

And maybe Katsu-kun was right and they were related because just then she broke out into waterfall level tears, something she had secretly considered a Midoriya family Quirk. "I love you ba-chan!"

Inko laughed and enveloped her in a hug. "I love you too, Nanako."

 **-[-]-**

Izuku put away his history notes and wiped the eraser bits off his desk. It was an unusually nice day outside after the almost week of rain and gloomy skies; he wished they could eat outside. As it was, even though they were allowed to bring their own lunch to school, they still had to eat in their classroom.

He stopped by the bathroom to wash his hands and shuffled back into class. There was a crowd around Kacchan's desk, but there usually was. He ignored it and sat down to dig into his-

"-bento from?" Tsukino asked, the moons in her eyes switching from crescent to full with excitement. (It was so cool how her eyes always showed the current phase of the moon. Would it still work if she was stuck indoors and detached from the day with artificial lighting? Why did the phase change with her emotion? Did she get any power boost from being out at night? What about full moons? What about-)

"None of your business," Kacchan snapped and finally undid the tie of the furoshiki.

Izuku was reminded that he also had food in front of him that he was neglecting in favor of eavesdropping. He pulled out his journal with one hand and unpacked his lunch with the other.

"Aw, c'mon Bakugo-kun!" Tsukino pressed. "Why so secretive?"

There was a small explosion and a shriek. "I said it's _none of your business._ "

The small crowd dispersed after that.

"Wow, Bakugo-san is so scary," Inoue (Quirk: water hair) muttered behind his hand.

"What? No way!" Goto refuted. "He's awesome! Ya gotta be strong in all ways to be a hero, ya know? Even if it's just food, you can't back down!"

"I guess..." Inoue frowned.

Izuku nibbled on his onigiri in thought. Kacchan hadn't brought a bento to class in years. The last time his mom tried to pack him one in second grade, he complained an awful lot about not "being a dumb baby" and that he was going to eat the school food from then on. Aside from school trips where they had to bring their own food, he kept to that.

So why now?

He surveyed the other boy out of the corner of his eye (if he was too obvious in watching Kacchan might throw his eraser again). The pattern on the wrapping cloth was a plain white grid on an orange background, not connected to any hero or show he could think of. The bento box itself was two layered, rectangular, and made of colored (painted?) metal with a removeable bottom for a heat pack or a note. He would know, he had the same type courtesy of-

Katsuki removed the bottom and a note fluttered out. The note was written on the same pale blue paper Nanako used for all his lunches. He shoved it in his desk before anyone else saw.

…

Why did Kacchan have one of Nana-nee's bentos? He didn't steal it, right? Nana-nee would have mentioned it on their walk to school. A-and she definitely would have mentioned if Kacchan had asked for a bento! Because even when he asked for Valentine's chocolate he was "just this side of rude, hm?" So!

Why did he have one? Why didn't she say anything? Was Izuku being... replaced?

 **-0-**

Five pm. The sun was barely setting. With autumn in full force, there was a bit of wind but nothing that his jacket couldn't handle. Sweaty older kids went by, some chatting animatedly and others wheezing with cries of "wait up!" A few spared him glances but no one approached him, not even the teacher carrying a heavy stack of notebooks.

Izuku waited solemnly at the gate of Meiho Middle School until, at last, a familiar head of messy black hair surfaced.

Nanako motioned lazily with her bagged gardening gloves to the girl on her right. Her head swung around in a heavy sigh, and when she lifted it her eyes caught his.

She lit up, a subtle thing, and turned back to the other girl. Other girl suddenly looked his way with a gasp and squealed something. Nanako rolled her eyes then they separated and she came up to him.

"Hey Izu-kun," she grinned and ruffled his hair. "Was there a hero fight nearby?"

He shook his head, throat thick.

"Ah, okay." She motioned to the street. "Let's go then."

He followed.

The route they took home was mostly residential, but there was a small convenience store and a laundromat.

Nana tilted her head to the side, "Want a snack?"

He shook his head.

She frowned. "You know, Izu-kun, I can _feel_ that you're upset about something. Is there someone you need me to knock out for you?"

His chest constricted painfully. He shook his head.

"Then..." she chewed on the corner of her mouth. "Would you like to talk about it? Or maybe, when we get home,-" he burst into tears "-we ca-aaAAHH IZUKU!"

Nana dropped her things. "What's wrong?! I'm sorry! Oh gods, what- shit, uhm, do you need a hug?"

He nodded through his tears and felt more than saw her wrap him in her arms and squeeze just so.

"Izu? Izu, what's wrong?" she said into the crown of his head.

"Y-you-you're replacin' mee-ee," he sobbed and tried to catch his breath. "With Kaacchaaan!"

"What?" She bit then huffed a sigh. "Izu-kun, I would never _replace_ you!"

"Liar!" His lungs crumpled into a sad little ball. "You made him a bento! A-and he has an awesome quirk! Why wouldn't you like HIM more than m-me?"

"I don't care about Quirks," she chided him. "And yes, I made him lunch, but not because I have any plans to replace you!"

"T-then why?" Izuku sniffed and rubbed his face into Nana's shoulder.

"I, uhm, took a joke too far and it's, uh, an apology," she explained and he could feel the heat radiating off her face. "But even if I did decide to start feeding him, he could never replace you because only you're you, okay?"

"... 'kay," a fresh round of tears came bubbling up. "I'm sorry, nee-chan!"

"It's okay," she brushed her thumb over his damp cheek and he felt a puddle of calm drip from the top of his head and down the back of his spine. "I love you, y'know? So you don't have to be sorry about this."

"I love you too," if he buried his face any more into her arm, he was going to become her conjoined twin.

Nanako hummed and hugged him tightly. Things would be okay.

* * *

 **A/N:** If I named my chapters this would be "Hidden Family Quirk: Waterfall Tears" or maybe "everyone says ily and by the gods do they MEAN it". Also I really wanted to draw parallels between Nana and her (found) family so keep your eye for recurring attitudes, speech patterns, etc!

(Bakugo doesn't know it yet, but he too has been adopted as Nana's little brother and the shared traits WILL show up eventually lol)


	9. Chapter 9

**A/N:** Would anybody like to see Nanako adopt Shinsou too? I've been thinking about it lately... and a quick note! Japanese has a pretty unique system for nicknames. While using -chan is pretty common, -pon, -chi, and more are also acceptable. See the ending author's note for a more in depth explanation.

* * *

Things were not okay. Things were not okay by a long shot.

Nanako stared down the villain in front of her. Armed with only a set of tailor's scissors and her trembling heart, she took a deep breath and raised the blades.

"Are you alright there, Nana-chan?" Inko-bachan's smile was clear through her voice.

She grunted, tongue caught between her teeth as she meticulously cut through the layers of flannel.

"Just let me know if you need help," she patted her shoulder.

She hummed. " 'kay."

Twenty minutes later, she had a strip of soft rectangles and squares pinned and arranged just like the picture on her phone. She grinned at the result and stood to stretch her arms.

"Ba-chan," she announced. "I'm ready now!"

"Alright, let me see," Inko set down her cup of green tea and poked through the proto-scarf. "Ooh, you have very steady hands. Good work with cutting the pieces out, Nana! Do you want to start sewing or should I do it?"

"I can do it," she gathered one strip of the scarf and set it at the sewing machine. Before she set her foot to the pedal, her aunt-in-all-but-blood adjusted her fingers and settled the trailing edge of the fabric to rest on the table and not her lap.

"Perfect," she smiled.

Nanako nodded and slowly began sewing the scarf, piece by piece. Inko sat at the table with her, calmly drinking her tea and looking at something on her phone, only the sound of the machine between them and Nana's mumbling when she moved onto the other half.

"Hey, auntie," she said and sewed down the short, raw edge. "How did you get so good at sewing?" A nice machine didn't mean the owner was any good, but some of Nanako's birthday outfits had been homemade and hard to pick apart from her store-bought clothes. Auntie had _skill_.

"I was in the fashion club in high school," she admitted with a light blush (it must have been a family trait to be so bashful). "The vice-president, actually. Before that, my mother taught me."

"Your mom?" she cocked her head and her sloppy bun threatened to spill out of its hold.

"Mm," she drank her tea, mood a little less bright but just as warm. "She passed away shortly after I graduated university, but she taught me a lot before then. I catch myself using some of her sayings from time to time too, which I never thought I'd do when I was younger!" She laughed, small tears in her eyes.

"Like what?"

"Well," she started- and then she was off! Her mother's sayings, her mannerisms, and most interestingly, her life.

Nanako listened between finishing one scarf and getting started on the next. Inko-bachan's mom (Ayame) had grown up near the sea to a rather poor family, and moved out to Musutafu when she was older to get a job as tailor's apprentice. A lifetime of making hers and her family's clothes put her in direct competition with the tailor's granddaughter. In the end, it was revealed that the granddaughter had been using her Quirk to bind the clothes together instead of learning the proper technique, and Ayame walked away the winner.

Granted, the sewing was done by machine and not by hand (otherwise a single t-shirt would cost an arm and a leg) but Ayame-baa-san knew her machine inside and out. Even if the other girl hadn't been cheating, she could've beaten her with her skill alone.

Inko wasn't as passionate about sewing, but it was a fun and useful hobby. She more so had a mind for numbers, hence her double degrees in accounting and administration assistance.

Nana modeled one of the finished scarfs to a round of cheerful applause and buried her face into the soft fabric to hide her blush. It felt, a little, like she really was part of the family and this was just a normal afternoon between mother and daughter, passing along heirlooms in the form of skills and history.

(She wasn't, because her real mother was in America saving lives, but she wanted it to be true so badly she _ached_.)

"I'm sure your friends will love their gifts," Inko broke through her thoughts with a grin. She swept up the fabric bits (cabbage) into the palm of her hand. "Ah, but what's this pile for?"

"I wanted to make an apron, but I think the pattern is a little too complicated for me." She dragged the fabric closer and rubbed it between her thumb and pointer finger. The pile was actually three different types of linen, but the bird themed and the colorful leaf ones were tucked inside the denim blue linen.

"Well, we don't have to finish everything today, Nana-chan," she reassured her. "You're welcome to come back over next weekend to finish up, or come over just because. You know I enjoy your company."

Nanako accepted with a blush-filled nod and helped clean up. When she laid in bed that night, linen neatly folded in its place of honor atop her dresser, she wondered if it would be presumptuous or cute to make matching aprons for her and ba-chan.

She was asleep before she could come to a conclusion.

 **-[-]-**

Kenta-nii had never delivered on that promised trip for getting good grades, but after talking it through with her mom, he managed to grab four weekend passes for a trip to Kamakura scheduled for just before New Year's.

And by "just before New Year's", Nanako meant "New Year's was that Tuesday after the weekend trip." And by that, she meant-

"Ah, no, it's okay!" She waved off Sayuri's hangdog expression. "Really, it's fine, Sachi. I know this was really last minute so don't feel bad."

"Mnm," she groaned and buried her face in her purple hands. "I'm still so sorry, Nanapon! If I had known earlier I would have totally told my parents to hold off on visiting."

She patted her shoulder with just a smidgeon of her Quirk active. It really wasn't anyone's fault that they had a loving extended family and thus couldn't take off to another town for a weekend trip right before a major holiday.

"Have you asked Tomomi?" Sayuri, the optimist, asked.

"Yeah," she sighed. "She can't go either. Her parents aren't comfortable letting her skip town without them and it's not fair that her siblings wouldn't get to go too."

"Ahh that's so rough!" She threw her arms around Nanako and released a cloud of pollen.

She sneezed into the other girl's hair. "Thanks. I really feel the love."

"You should!" She rolled her eyes. "You know we would totally go if it was up to us!"

"Yes, I know," she wiped her watery eyes and brushed what pollen she could off her skirt. "I just don't know who else I could take... Maybe I can convince Kenta-nii to not third wheel me if I ask his girlfriend to go with us?"

"Or you c-"

"I'm not dating someone just to take them on a trip!" She jabbed her side.

Sayuri detached with an "eep!" and nearly rammed into Tomomi.

"Ah, Sachi can't go either?" She held out their drinks; iced coffee for Nana and strawberry milk for Sayu.

"Nope," Sayuri wasted no time popping open her milk and slurping it.

"Well, on the bright side-"

"There's a bright side?"

"- _Yes_ , there is, you pessimist," Tomomi rolled her eyes. "And it's that you can take your cute little brothers with you! Or at least one of them, right?"

She shifted uncomfortably and fiddled with the pop tab of her coffee. "I guess I could..."

Well, her first pick definitely wasn't Katsu-kun, as fond as she was of the brat. Still, wouldn't it be _weird_ to invite her neighbors/the Midoriyas on a trip with her? They weren't even tangentially related, and she'd been very thorough in checking with the information she had available.

"It would definitely feed into your brother complex, and that's always good for your mood," Tomopi, the traitor, added from behind her can of black tea.

Nanako couldn't even deny it, though she could knock the other girl out- and did. Sachi suddenly had her arms full and Nana snickered before easing up on her quirk.

"Tomopi is right, take one of your little brother harem with y-"

"IT'S NOT A HAREM!" She covered her face with her hands.

"Not yet," Sachi, the other traitor, added with a foxish grin. "Mark my words, Nanapon! One of these days you're going to wake up and find that you have a harem of guys all begging to be doted on by you!"

"Don't curse me like that!" She hissed to both of her _horrible, traitorous friends'_ joy. "I'll DIE first!"

Needless to say, nothing productive happened after that.

 **-[-]-**

A sharp wind rushed through the tiny balcony, chilling Nanako to her bones despite the heavy blanket wrapped around her shoulders. Her fingers burned where they touched her mug of cocoa, but the outer edges of her knuckles stung with the cold. A faint layer of snow dusted the roofs for as far as she could see, which was a feat in itself because being at the sea's edge meant the weather rarely allowed for such a chill.

Just off the hotel, the waves crashed in a soothing lull against the sandy shores. Distantly, she could hear the train crossings but no cars; everyone was already home and settling in for the moment the bells tolled out the old year. It would start any minute now, as soon as the clock struck eleven, 108 strikes to match 108 bad emotions to leave behind.

The balcony door slid open with a very human hiss.

"Cold!" Kenta closed the door behind him and shuffled over to where she stood.

Nanako sipped her cocoa. It was still hot enough to steam, which warmed her chin.

Her cousin shifted in place. "There a reason you're out here?"

She shrugged.

"Ah, so eloquent," he ruffled her hair.

She scooted a step away, but couldn't avoid his assessing gaze when he twisted himself in front of her.

"I don't have a mind reading quirk, ya know?" He smiled ruefully. "What's up, Nana?"

Hot shame flooded her throat and she looked at the floor. It was childish and dumb, what she was feeling, but... "This is our last New Year's, huh?"

"Wha?" Kenta-nii stood up before he fell over. "What makes you say that?"

"You're going to graduate when we go back," she gnawed her bottom lip between her teeth. "And I'll be in high school a week after that. So. You'll get a job. A-and move out. Right?"

"Uh, well," he covered the back of his neck. "I mean..."

"It's okay," she drew her blankets closer. "I saw the email chain with my mom." It spanned a few months but the most recent ones were about her maybe going to the high school she wanted and him moving out.

"You did?" He winced. "Mm, uh, that definitely wasn't the way I wanted to tell you... but it's not like I'm moving out the day I graduate or anything, Nana. We've got months until then- and it's not like you're never going to see me again!" He threw an arm around her and shivered when the cold seeped from her blanket to his arm.

"Even when I move out, I'm still going to bug you all the time- it'll be like I never left!" He squeezed her into his side.

"If you say so..."

"I do," he said with such conviction that her head lifted of its own accord. "I promise I'm not just going to leave you all by yourself, even when I do make it big and start selling my cool triple A level games. I'll even make it my assistant's job to come by and check on you, with towers of food!"

Nanako rolled her eyes with a smile. "Try getting a job first, nii-chan."

He gasped in shock and ruffled her hair even more. "You brat! How dare you doubt the great and mighty Kenta-sama!"

"My cocoa!" Her bangs were so messy she could barely see her own hands but she moved the mug away as far as possible.

"Don't worry, I'll buy you two hundred cocoas," Kenta thumped his chest. "And an extra hundred when you have exams!"

"Mah, mah, I get it!" She shoved her hair out of her face. "Even when you go, you're not going anywhere. You don't have to be so extra about it."

"Being extra is in the Hayashi blood, little cousin," he grinned. "Now let's get inside before we're extra frozen."

Nanako sighed but returned his grin. "Okay."

 **-0-**

It was a cloudless spring day a week before the cherry blossoms bloomed when Kenta-nii graduated. Two months later, one of which was spent harassing her about home security and more self-defense lessons, he pressed a kiss to Nanako's forehead and moved out his last box of things.

She went to bed with a familiar emptiness and woke up to the irrefutable fact that she was living the life of an anime protagonist- which, no. Just no.

She promptly rolled over and went back to sleep, not willing to exert the energy to panic over it or give the thought any more attention. She was just fine being a background character, thank you, and when she finally went on summer break in a couple of weeks, she was going to turn Kenta's room into a plant nursery.

* * *

 **A/N:** Hope you lovely readers enjoyed :) And please do let me know if you'd like Shinsou to be adopted too- I have ideas on how to implement that lol

An explanation of Japanese nicknames: they're versatile! The most common ones I've seen are part of the First Name+a cutesy bit. "Kacchan" breaks down to the "Ka" of Katsuki and "-chan", but since it's all mushed into one word you double up on the "c" and drop the hyphen. Nanako, using -chan as our cutesy bit, would be "Nacchan" or "Na-chan" or "Nana-chan." "Nanako-chan", on the other hand, is a familiar/cute way to refer to Nanako but I don't think it qualifies as a nickname, so to speak. Then again, I'm not a native Japanese speaker so if you are, feel free to shoot me some resources I can look at to improve!

You can also use -pi, -pon, -chi, -tan, -rin, -run, and -kun. You can use the first syllable or syllables for nicknames, or you can mash the person's first AND last name together. Our favorite ponytail hero Creati is an example of that last one- she's called Yaomomo ( **Yao** yorozu + **Momo** ). There's also nicknaming someone after one of their traits or coming up with a nickname from their last name, though these seem to be less common.

Of course, you can drop the cutesy bits and honorifics all together and just call a person by their name, but that's not a nickname. Rather, it's a way to signal that you and the other person are close! What kind of "close" varies on your relationship but usually it's familial, near-familial (like childhood friends), or romantic. It's been the source of some truly hilarious misunderstandings and juicy drama in the anime/manga I've seen, let me tell you! Anyways, that's enough out of me. Hope this helped to clarify things!


	10. Chapter 10

**A/N:** For the curious/confused, there's a short breakdown of the Japanese foster care/orphanage in the ending author's note. It will be relevant for later. Also, any "best boi/best girl" arguments in the chapter are purely for _flavor_ and not an invitation to start a waifu war in the review section lol

* * *

For obvious reasons, Katsuki had his own phone. For even more obvious reasons, Nanako didn't have his number. She did, however, have Mitsuki-bachan's number so that was who she called when she finally finished planning out how she was going to renovate Kenta-nii's old room.

There was the usual small talk (ba-chan had just gotten a call from her agent about a shoot they wanted her to do, Nana was steadily working through her summer homework) when she dropped the question she'd been holding onto since she decided to call.

"Hey, auntie, does Katsuki still have that spiky little house plant?" She fiddled with the end of her ponytail. "The one with the red edges?"

"House p- ah, that's where that came from!" There was the sound of a palm coming down on something- had auntie really smacked her knee? "Yeah, the brat's still got it. Keeps it in his room and everything. Why, do you want it back?"

"Ah no, no," she let her hair go to grab her clipboard from the cushion next to her. "My cousin moved out-" "Kenichi?" "-Kenta; And I wanted to switch his room to a greenhouse kind of thing, but it's a lot of work to do it by myself, ya know?"

"Go on," Mitsuki-bachan drawled with an obvious smile.

"So, if he's okay with it- and if you and Masaru-ji-san are okay with it, of course- do you think you can send him over here to help me out with that?" She flipped through the pages of notes, of scribbled designs and amateurish drawings of plants.

"Ha! Can I?" A chair scraped across the floor. "You bet your sweet little face I can!"

Ba-chan sucked in a deep breath and Nanako moved the phone away as fast as she could without accidentally flinging it across the room. "HEY BRAT! YOU GOT A JOB!"

She couldn't hear Katsuki's reply, but from the way auntie continued to holler, then yell when she apparently got closer to Katsuki's room, she could guess what was going on.

"-Hello?!" Katsu-kun's voice was piercing, but he wasn't yelling so Nana warily brought the phone closer.

"Hey," she replied with a casualness she barely felt. The Bakugous were so energetic... "I'm converting my cousin's old room to a greenhouse. Wanna help?"

"... how old are you?" He glared (she could feel it).

"Almost sixteen," she frowned (what did that-) then clamped a hand over her ear when he started yelling.

"WHY DOES SHE GET TO LIVE BY HERSELF AND SHE'S ONLY FIFTEEN?"

"SHE'S RESPONSIBLE, UNLIKE YOU, YOU UNGRATEFUL BRAT!"

"I'M RESPONSIBLE!"

"ANSWER THE QUESTION FIRST!" There was a beat of silence. "AND I STILL DO YOUR LAUNDRY, HOW ARE YOU-"

"Yeah sure, I'll be right over," Katsuki said over his mother's ranting.

Nanako looked at her phone. "Call ended" flashed twice before closing out.

Well. That solved that... even if she hadn't actually bought anything yet. Maybe ba-chan would take pity on her and drive them around to get things?

A girl could hope.

 **-[-]-**

Katsuki was a very smart boy- top of his class in terms of grades, well-respected by his classmates (despite his disdain for them), and incredibly athletic. He was also very cute when he wasn't pulling horrible little faces so people would stop comparing him to his (model) mother.

What he wasn't was _patient_.

"Hey, Nana-witch," he groused around a mouthful of mongolian barbeque not three minutes into their meal. "Why're you always babying Deku?"

"Hm?" She stared flatly at him.

"You heard me." He asserted and shifted in place on the couch when her gaze didn't falter. "You're always babying Izuku, like pattin' his head and praising him _all the time_ for little shit. Why?"

"Well, why not?" She shrugged. "Good kids should be rewarded."

His cheeks puffed up with an angry flush. "You don't do any of that with me! You saying I'm not a good kid, huh?!"

Ah. Now she got it.

"Let me rephrase that," she sighed. "Izu-kun is a good kid, but no one ever tells him that except for ba-chan. I think he should hear it more, so I'm more generous with praise for him. You, on the other hand... well, I've heard your classmates talk. Some of your teachers too. You already get a lot of praise, don't you?"

He glared at his lap, which was confirmation enough.

"So that's why," she nodded decisively. It was more than she was used to saying in one go, but being clear was better than being brief in this case.

They ate in strained silence. Katsuki had a sullen look to his face but honestly, what more could Nanako do? Izuku never stopped talking about how amazing the blond's quirk was and how he was going to become a top hero and their classmates clearly favored Katsuki. Hell, during the few times she dared to ask their teachers, they'd been incredibly sparse with positive feedback for Izuku but overflowing with it for Katsuki. He had both parents and they loved him, though they weren't afraid to occasionally call out his less than polite behavior.

More than that, she just plain didn't hang around Katsu-kun as much as she did Izuku. Izuku invited her along to his hero watching expeditions once or twice a month, and the **few** times she'd gone he'd been over the moon with thanks and talked her ear off over snacks. Until she'd called Mitsuki-bachan, she hadn't even been sure Katsuki had kept the plant she gave him.

Actually, when she'd given him Mr. Ukki (what she'd privately named the houseplant) he hadn't properly asked for it or even thanked her! He just waved off her explanation of what it was called and how to care for it, complaining of her "nagging".

(Something dark twisted in the pit of Nanako's stomach. She wanted to tell him to pack his bag and go home instead of staying over for a movie night like she promised.

Wanted to... but it wasn't like he didn't have a point. When had Nana ever praised him? Ever thanked him to the degree that she did with Izuku instead of accepting his helpfulness as a fact of life? When she singled him out, was it always to complain about his attitude, his tone?)

Nanako got praise from her teachers and friends, and plenty of help from her cousin before he moved out. Rarely did her mother ever acknowledge her achievements except as a matter of course. Mostly she pointed out Nana's short comings, asked why she hadn't gotten tutoring for even better grades or done more to involve herself with a club.

She knew exactly how he felt, wanting that _one_ person's praise because they were so tight-fisted with it.

Her chopsticks clacked against the coffee table as she set them down. "Hey, Katsu-kun?"

He grumbled, shoulders hunched and turned away.

"Thank you for coming over to help me today," she reached out and ruffled his hair with a grin. "You're good company and I would have never finished everything so quickly if it weren't for you."

His head turned further away, but he scooted closer. "Whatever, witch. You're welcome, I guess."

Oh this brat- "Witch, hm?" Her hand traveled down from his hair to his cheek. She pinched it and cackled when he tried to pull away. "Well finish eating then so I can start cooking you!"

"Stahp et-" Katsuki whacked her hand away and shuffled to the far end of the couch, one hand on his red cheek. "You weirdo!"

She clutched her stomach as she laughed; Katsu-kun was back to normal.

 **-[-]-**

With a summer to decorate, the apartment had come a long way from the gutted, half-empty shell Kenta's moving away had left it. Katsuki had helped her set up the bare bones of the spare room (shelves, lights, humidifiers) but the real change had come when Tomomi and Sayuri came over armed with washi tape and determination. Sayu-chan decorated all the pots while Tomopi arranged Nana's collection of keychains on a cork board. The two of them squabbled over how to arrange the string of faux-polaroids she'd printed out and she stopped them from wrestling holes into the walls.

Because she was a teenaged girl living on her own, she had no shame in moving her anime wall scrolls from her bedroom to the wall behind the couch with a (tiny, not at all creepy) shrine dedicated to her various faves. Mostly it was a few pictures and one or two packaged snacks, but Sachi had gone as far as to "bless" it with a tiny bundle of sage and say a ridiculous prayer for good luck and good grades.

Tomo-chan doused the smouldering sage before it could set off the fire alarm. "Hatake-sama," she sighed. "Please help these idiots not burn down the house."

"You think I like Kakashi's old ass?!" Nanako shrieked, sharp enough to catch both of her best friends on their back foot. "Minato is my only ninja love! Pray to him instead!"

She threw her hands up. "I don't trust anybody related to Naruto! No good sense came out of that gene line and none ever will."

Sayuri gaped at the both of them. The proverbial gauntlet had been thrown down.

(Later, they would gather around to discuss how to get through to her new, quiet student and even make concrete plans. For now, Nanako had to defend the Namikaze honor and prove why her quiet, devoted love trumped Tochi's cold logic when it came to determining who was best boi.)

 **-[-]-**

When most people thought of an all-girl's high school, they thought of a secret paradise full of sweet, charming maidens... demure young ladies who were dedicated to their studies... with soft, polite speech, proper manners, and delicate laughter that drifted down the halls...

"It's so hot I think my tits are gonna melt off," Haruka grumbled and scrubbed the sweat off the back of her neck.

"I think you could use my bones for fortune telling," Nanako poured water on her handkerchief and patted her face. Ah, evaporation, her old friend!

"Why do we have to do gym in this kind of weather?" She undid one of the straps of her pinafore to get at her damp armpits. "Do the teachers wanna kill us? I bet they do- especially Noguchi. Bastard."

"Ugh, just be grateful you sweat perfume," she dreaded the state her scalp would be in after running a mile with her hair braided as tightly as her hands could make it. All that dead skin and oil- she could just cry. "Unlike us lowly mortals who come out of gym smelling like a zoo."

"Hey, it's not all sunshine over here," she waved her sweaty (floral scented) handkerchief around. "This stuff stains, ya know?! I'm always doing laundry!"

She rolled her eyes and pulled out her lunch. "How sad."

"At least pretend a little," she groused and pulled out a Mightade.

Mightade tasted like cheap banana flavoring and salt. She knew because she bought a four pack on sale on a whim and ended up throwing up half of it. It had _nothing_ on Endeavoraid, which had a lovely cherry flavor and made the best treat when half frozen.

"How can you stand to drink that crap?"

"I dunno," Haruka shrugged, one strap still hanging off her shoulder. "It's an acquired thing, I guess. The aftertaste is pretty good."

Nanako scrunched her nose at the thought. They ate lunch in relative peace (it was too hot to keep complaining) then cleaned up.

"Hey, Hayatan, you signed up for tutoring again right?" She drummed her fingers on the desk.

"Yup," she flipped through her notes. Spring term had been focused on chemistry but now they were moving onto genetics and biology as her many pages of Punnet squares could attest. "The workers seem to like me and it means I don't have to deal with the _little_ little kids in this heat."

"Ah?" she cocked her head to the side. "But they're so easy! Just shout some encouragement or offer to play with them and poof- all their problems are gone! Not like the brats at the tutor center..."

"You're just mad that one girl pointed out your English was wrong," she deadpanned.

Haruka threw up her hands. "If she's so good at it, why is she going to tutoring, huh?! Just cause her little friends are? Get real, brat!"

"Irin," she buried her face in her hands. "Are you really complaining about an orphan wanting to hang out with her friends?" Especially since Haruka had only tagged along to hang out with Nanako on that day.

"Or- orphan?" She paled, a feat for her golden brown skin. "What?! What do you mean?"

She blinked, but the scene remained as clear as ever. Haruka Ito, age sixteen, sat to her left in their Amidura school uniform with her messy side ponytail and scrunched socks. She had an All Might lead pencil in her hand and a bottle of Mightade on her desk. It was almost time for science class to start.

"Ito-chan," she said slowly. "Did you not notice that... our school does a lot of charity and works with a lot of little kids?"

"Well duh," she regained some color in her cheeks. "But how d'you get orphans from that?"

"... Well. When we had to sign up for places to volunteer." The words fell out of her like wooden blocks. "The tutoring center said, 'Saint Kurosan **Children's Facility** '. So."

"Is... 'children's facility' uh, code for orphanage?"

"Pretty much." She couldn't think of a single orphanage in the country that literally had 'orphanage' in its name. It was too "shameful" or some shit, apparently.

"Oh." Haruka scribbled a flower in the corner of her notebook. There was a sudden swell in perfume. "Well. I still like playing with the toddlers more."

Nanako was still laughing hopelessly into her hand by the time Iwasaki-sensei sauntered in.

* * *

 **A/N:** Hope you lovely readers enjoyed!

Please take everything I'm about to say with a grain of salt as I'm no social worker and I'm definitely not a Japanese social worker either! Also, this is in no way meant to hate or glorify any one country, but rather to explain some key differences.

In Japan, fostering is just... not a thing. Like, yes, it exists but few people sign up for it (at least, in comparison to the USA) and there is no government aid for doing so. Mostly, it relies on people's goodwill and their ability to weather the stigma of taking in+raising a child that's "not theirs." (I am firmly of the belief that family is what you make of it and if you disagree, stop reading.) The far more popular option is that children are placed into a "Children's Facility" and never adopted or fostered. A good number of cases are not from the parents giving up the child/ren so much as the parents being declared unfit due to abuse/neglect, but refusing to give up their custody rights hence why the child may never leave that facility. Even with government aid, these places are overcrowded, underfunded, and understaffed. There is basically no social net in place to help former foster kids attend college, get a job, or attain food+shelter once they age out of the system.

In the USA, by contrast, fostering is a much more widespread and widely accepted thing. The government has largely shut down orphanages in favor of group homes and private foster families. Don't get me wrong though, the foster system is still crowded and susceptible to abuse or neglect, and "more" accepted does not mean "totally" accepted. There are still people who think fostering/adopting is "weird" because the child in question didn't come from the foster parents' bodies, but again, those people can stop reading at any time. While there could definitely be more support to help former foster kids, financial aid on the state and federal level exists specifically for this group which seems to be lacking in the Japanese system.

All of this to say, it's not my intention to misrepresent the foster care system of any country, but this is fanfiction. While I hope to stay faithful to and respectful of the experience people in foster care have gone through, I'd also like to pretend the world of HeroAca is a bit better than our own and therefore change some things up for the better. I hope you lovely readers will stick with me- and keep yourselves safe out there!


	11. Chapter 11

**A/N:** Short and sweet because it has been... a week. Stay safe out there everyone!

* * *

 **February- 5** **th** **Grade**

Izuku sat at the table, swinging his feet while his mom puttered around their small, colorful kitchen. The wonderful scent of katsudon filled the air and his stomach grumbled impatiently. Before he could work up the courage to ask his mom for a taste test, the sound of a small stampede rushed up the stairs and stopped outside their front door.

Mom shook her head fondly and motioned for him to let in their guests. He hesitated because, uhm, did Nanako always sound like that? And Kenta-nii... that had to be him wheezing right?

He cautiously hopped down and went to open the already unlocked door. His back slammed against the wall as Nana fell inside the doorframe while clutching a thick stack of envelopes and... praying?

"Nana, I swear to all the gods- and I do mean _all_ of them- if you don't hurry up!" Kenta-nii picked the younger girl up by the arms and frog marched them into the hall.

"O Namikaze-sama, o golden genius of the leaves," she muttered under her breath, ignorant to the manhandling or the fact that Izuku was standing _right there_ and she hadn't greeted him properly yet.

He closed the door with a perfectly neutral expression. Definitely not a pout, because he was too old for things like that and heroes didn't pout.

"Hey Auntie," Kenta greeted his mom and shoved Nanako into a chair right next to Izuku. "Thank you for having us over."

Mom laughed. "Hello Kenta, Nanako. I take it somebody got some exciting news?"

"Amidura! Yaei!" Nana squeaked, envelopes crushed to her chest. "Kaisei! Super Science High!"

"Didn't you also apply to Hidan Women's Academy?" Kenta sat across from him, out of Nana's direct line of sight.

Her face contorted in disgust- similar to Kacchan, funny enough. "If anyone here or otherwise thinks I'm going to sit around to learn tea ceremony and horseback riding they have another thing coming!"

She fished out a manila envelope and slapped it on the table. Written in nice calligraphy was Nana's name, address, and the academy's motto. There was also the school's emblem which... was a horse head?

"Someone else open it if you want," she leaned into the side hug his mom gave her. "I already have the ones I care about right here."

Kenta laughed and flicked the envelope Izuku's way. "Go 'head, pipsqueak."

Well, if they insisted... He opened it by tearing the corner with his teeth (ew, glue tasted disgusting) and pulled out the decision letter. "You got in."

"Keep it," Nana sighed. "I don't want to have to move into dorms all the way on the other side of the city just for flower arranging lessons."

Did Hidan offer ikebana classes? He picked through the rest of the packet while Nana pulled a letter opener out of her pocket (she didn't think to share earlier?!) and went at the other envelopes. (Also Hidan did, in fact, offer ikebana. It also offered etiquette, math, tea ceremony, literature, astronomy, poetry...)

"So how're you gonna reveal this?" Kenta poked at the line of folded letters.

"Super Science first," she nodded.

"Why that one first, Nana?" Mom turned the stove off and plated the last katsudon. The sharp crunch crunch of the breading being sliced had his mouth watering. "Is it your top choice?"

"Ah, opposite actually," she smoothed the paper. "Super Science has really good university acceptance rates, but it's all for _Hero Support_ and things like that." Her nose scrunched in distaste.

(He tried not to take it personally, because it was okay to have different interests, but did she have to sound like _that_?)

"Then why'd you apply?" He pushed the Hidan pile aside.

"It's good to keep my options open," she nodded. "And hey- I got in, sort of! They put me on their waitlist."

"Ha, you're both each other's 'maybes'," Kenta stood and helped get glasses down for dinner.

She hummed and passed him SS's letter. "Now Yaei... accepted!" She beamed and tucked that one to the side.

"Congratulations," Mom set down the platter of katsudon and the pot of rice.

"And Kaisei... ah." She handed it to him.

"Screw 'em," Kenta huffed defiantly- then ducked his head with a mumbled sorry when Mom side-eyed him.

"Well it's not like all of them could be acceptances," she shrugged, twisting the last letter in her hands.

"I think wherever you go will be lucky to have you," he asserted loyally. (He was still a little miffed at the clear disdain for hero support but she needed cheering up. [It was fine that she didn't want to be a hero but she could totally support him from there! She should _really_ think of all the possibilities...])

She smiled at him and tracked Kenta as he set down water for everyone. There was an undercurrent of tension, but in a good way, as they all dug into the food and Nana continued to fidget in place.

"Alright, last one..." She announced with a deep breath. She took another deep breath, held it, and read the letter.

Izuku's stomach clenched with anxiety (his own, not a spillover from Nana) as her face froze. When tears welled in the corners of her eyes, he found himself launching from his seat to throw his arms around her shoulders.

"What's it say?!" Mom had picked up Nana's fidgeting.

"I..." The letter crumpled in one fist, the other hand coming up to hold his arm. She was shaking, just a little. "I got in on a partial scholarship!"

They cheered, because of course they did, and by the time he sat down Nana was coherent enough to start gushing about "Amidura." After she nearly punched her water off the table for the third time, he uncurled her fist and took the letter to read.

Nana's joy was a bubbly thing, but it wasn't as infectious as her ever-present chill or her rare panic. He let it wash over him as he picked through the school's offer in between bites of his favorite dinner.

It was a good school. Not as great as it would be if she decided to work in Hero Support after going to SS, but a good school nonetheless. They had this thing about community service, and a gardening club that boasted a three-fruit citrus tree. He could totally see Nana being happy there- except for one little thing. Well, it was kind of a big thing.

"Nee-chan," he swallowed a mouthful. "You realize this is an all-girls' school, right?"

"Yes...?" She furrowed her brow. "It's in the name."

"But..." And it was- Amidura Girls' High School. Right there. In bold, flowing script. It made his eyes itch. "I don't want to have to push you down the stairs! Or off a bridge! Or turn you over to an alien research lab!"

Mom spit water _everywhere_. "WHAT?"

Nanako covered her face with her hands. It was going to be a long night.

 **-[-]-**

 **September – 6** **th** **Grade**

Nana had given Kacchan a houseplant last year. Nana made Kacchan a bento. Nana invited Kacchan for a sleepover when Izuku went to Didney Land for his birthday over the summer.

But she also said that she wasn't trying to replace him, that no one ever could, and he believed her.

Nana liked gardening, and hanging out with her friends. She didn't like heroes or workaholics. She once spent an entire afternoon ranting about never-for-as-long-as-she-lived going to an all-girls' school and what to do if she ever "lost her damn mind" and went to one.

But now she was going to an all-girls school, and happy about it, just so she could do _more work_ on top of her club and homework.

Izuku's head was going to roll off his shoulders.

His big sister, the first person that he truly felt safe with outside of his mother and All Might, was someone he didn't understand anymore. He wasn't even sure when it started, when she had begun to change. Had it been happening all this time?

He prided himself on very little, but his ability to analyze things was part of that short list, and it had _failed_ him, somehow.

But he wasn't a quitter! He wasn't just going to see that Nana had changed and do nothing about it. First, however, he needed info. That was easy to come by (she lived right next door and almost always let him come over) but also not. What sort of information was **good** information?

The scientific method might have stressed that a large pool of data and observations were important to draw a good hypothesis, but people were much more complicated than the laws that determined the shape of a flame or a raindrop. He couldn't even say how he would act every single day, and he was himself!

Okay, so scientific method aside, he needed something that would help things make sense, but what? A personality test? But that would only give her "type" as it was now, not whatever it was before, and it wouldn't explain why she had changed so.

He scribbled down a few base facts about her while the TV played a clip of MiniMo fighting some villains.

"Taking notes, Izuku?" Mom plopped on the couch and settled the basket of laundry at her feet.

He shook his head (it was a rerun) and added more bullet points. Kenta-nii had moved out in June... given that, and the fact that she was now a first year high school student, they'd lived together for...

The familiar cloud of his mom's perfume enveloped him as she nuzzled her cheek against his hair. "Ah, so it's not Hero notes today, but Nana notes, hm?"

Izuku paused mid-writing as the obvious occurred to him. "Hey, kaa-san, do you know what's different about Nana-nee lately?"

"Different?" She squeezed him a little tighter then sat back.

"Yeah," he nodded three times in a row. "Like, lately she's been baking more but there's never any left when I go over! And she didn't used to want to do more than the minimum but now she's got club _and_ tutoring, y'know?"

"Hm, I wonder..." his mom crossed her arms with a smile. "Have you noticed how cute Nana has been doing her hair lately?"

"Yeah!" He was so glad Mom was also seeing all the weird new changes too! "It used to be a ponytail but now she does braids and low pigtails- and even your hair style!"

"Her face too," Mom added with a tap to her chin. "Something is different but you just can't put your finger on it, right?"

Izuku really should have consulted him mom earlier because she was a wellspring of information and living proof that he wasn't just seeing things. "YEAH!"

"Well the big 'change'... is puberty!"

"..."

"You remember our talks-"

"Yeah..." he stared at his notes in dismay. He had been prepared all sorts of things- her Quirk evolved, she'd been replaced by a pod person, she'd been replaced by an alternate universe of herself where she became a Villain- but he hadn't considered something as basic as growing up.

Izuku packed up his notes with a slump to his shoulders. Mom wouldn't stop giggling at him as she started folding laundry. He made it to the hallway door before a chilling thought hit him.

"Mom... am I going to change like Nana-nee?"

"Well, no, not exactly," she set down the half-folded towel. "It's different for everyone."

He nodded. In the safety of his room he patted his stack of Hero Notes solemnly. "I'll never give you up, no matter what happens."

Honestly, of all the things to have missed...

* * *

 **A/N:** I toyed with making this chapter an AU or something, but in the end, having Izuku be stumped over something that's completely normal was just too funny to pass up. Maybe in the future I'll have Villain!Deku come into this world or bodyswap Nana and him just for shits and giggles- but I've already got a lot of plot threads running and I need to chill haha

Also, at the time of posting this, Efficiency has 99 reviews?! That can't be real! I'm beyond flattered and I would die for y'all just say the word

I hope you lovely readers enjoyed! See you next time :)


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